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SOFREL PCWin - OPC Server Function Specifications File V 2.34
SOFREL PCWin - OPC Server - Function Specifications File - V 2.34
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LACROIX Sofrel 2, rue du Plessis 35 770 VERN SUR SEICHE Telephone: 02 . 99 . 04 . 89 . 00
Fax: 02 . 99 . 04 89 . 01
SOFREL PCWin - OPC Server Function Specifications File
Reference........ : PCW-DSF_OPCV232-ag.doc Version ........... : V 2.34 Date ................ : 18 June 2007 Classification.... : Public
By.................. : Gilles ROUAULT
Approved by........ : MB
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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LIST OF UPDATES First version Previous version
: 1.10 : 2.33
Date: 09 / 07 / 98 Date: 26 / 10 / 05
DESCRIPTION OF MODIFICATIONS Date
Name
Paragraphs
Reasons V 1.11 :
24/9/99
GR
References
Added reference [1] and renumbered
1.1
Added reference [1]
2.3.2.1
New paragraph
2.3.2.2
New paragraph
2.3.2.3
New paragraph V 1.12 :
22/10/99
LL
2.3.2.1
Modified description of the ACK item
GR
2.3.2.1
Added explanation on HOLDCOMM and STOPCOMM Added SENDING item and modified description of ACQUISITION V2.10
05/05/00
LL
14/11/00
LL
Document entirely overhauled document V2.11 2.2
Added trace levels; TraceLev in [Global] section
2.4, 2.5 et 2.8.1
Description of HISTRATE item
2.7
Added BASERATE parameter
2.8.3
Details on UPDATE item
2.8.3.3
Description of SECTION3 corrected V2.12
09/03/01
LL
2.4
Description of functioning of HSTARTNOTIFY for handling initial history values.
2.5
Description of functioning of HISTPOLL for handling stampdated value searches. V2.13
11/12/03
LL
2.5
Description of the functioning of history polling from V2.0.23. V2.30
02/03/04
PL
2.8, 2.3
7/04/05
LH
2.2
Added groups of stations from server version 2.0.30. V2.32 Addition of a level of traces operator to replace the traces meter of reference from server version 2.0.32.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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V2.33 SG
Change of document number to match server version. V2.34
24/04/07
LH / SF
3.2.1
Addition of the AlwaysNotify key
2.8
New pagination
2.3
Deletion of the paragraph covering OCCibleNotification mechanism implementation
2
Addition of a general architecture diagram
2.5
Archive management: the archive viewing summary/history alternation no longer exists. Each item is dealt with according to type (history or summary). Addition of the description of the new viewing mode implemented from this version 2.0.34.
3.2.1
Addition of the “Lot” key
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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REFERENCES
[1] OPC Data Access Custom Interface Specification V1.0a (OPCDA10A.doc) [2]: OPC: OLE for Process Control: a communication standard based on OLE/COM technology, which is the new data exchange method between MSWindows applications.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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CONTENTS
1. INTRODUCTION
7
1.1 Purpose
7
1.2 Reference documents
7
1.3 Terminology and abbreviations
7
1.3.1 Terminology 1.3.2 Abbreviations
2. DESCRIPTION OF FUNCTIONALITIES
7 7
8
2.1 Starting PCWin
8
2.2 Trace management
8
2.3 Browser management
10
2.4 Managing time-stamped values
10
2.5 Managing archives
11
2.6 Multiple client management
12
2.7 Asynchronous communications management
13
2.8 OPC items
13
2.8.1 2.8.2 2.8.3 2.8.4
SYSTEM Variable Station parameters Station variables Station group parameters
3. OPERATING CONDITIONS
14 16 17 22
23
3.1 Operating environment
23
3.2 Configuration file
23
3.2.1 Main configuration file 3.2.2 Station configuration files
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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1. INTRODUCTION 1.1 Purpose This document presents OPC server implementation specifications based on SOFREL’s PCWin software. The server implements the functionalities of the OPC 2.0 standard.
1.2 Reference documents Reference OPC standard
Title Data Access Custom Interface Standard v2.0 June 19, 1998
External SOFREL Document
Interfacing PCWin with a OPC v1.70 server
1.3 Terminology and abbreviations 1.3.1 Terminology PCWin is a remote monitoring and control software package for SCADA central stations developed by SOFREL. It provides data access to SOFREL remote terminal units and centralizes the data on the SCADA central station. PCWin can be controlled via a PLC based on OLE Automation. The PLC is used in PCWin’s client software.
1.3.2 Abbreviations Not applicable.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2. DESCRIPTION OF FUNCTIONALITIES The functionalities available in the SofrelOPCServer server allow standardized access to the data in Sofrel supervisory control stations and the PCWin software package. Data access is based on COM/OLE technology and occurs via OPC 2.0 interfaces. Optional interfaces are only implemented if they can be of any use in a server running PCWin. The SofrelOPCServer server is available in two versions, which are functionally identical with regard to the OPC 2.0 standard. The first version is an in-process server (implemented though a dynamic library), and the second version is a local or remote server (implemented in an executable). Sofrel OPC Server
PCWin
OPC
OPC Client
2.1 Starting PCWin The SofrelOPCServer server starts PCWin when first connecting, if PCWin is not already running. It does not shut down PCWin when it stops, because it is not necessarily the only PCWin . However, it is possible to force PCWin to stop using OPC function “SYSTEM/STOP”. When PCWin is not running, an OPC client can restart it using the “SYSTEM/GO” function.
2.2 Trace management The SofrelOPCServer server transmits traces during the main operations that occur while it is running. The traces issued are classified by trace level. Trace levels represent trace category groups, which can all be independently activated through bit combinations. The existing categories of traces are listed in the following table: Index of bit in level 0
1
Prefix used for this Active trace category category IN/OUT Input/output trace for functions
1
2
ACCESS
Accessor call trace (values read and written)
2
4
CYCLE
Trace of object lifecycle destruction)
3
8
ALGO
Trace of algorithm usage
4
16
CALLS
Trace of function results (parameters and results of the call)
5
32
OLE I/O
Input/Output trace OLE interface methods
6
64
OLE CALL
OLE interface methods result trace (parameters and results of the call)
7
128
SUIVIOP
Operator-level trace (functional monitoring with the names of items OPC in light)
NO TRACE
Reserved
8 to 31
Trace level
events (construction
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
and
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The prefix is a character string placed prefixing the trace message proper identifying the category the message trace. The trace level is a global operating parameter of the SofrelOPCServer, which is defined even when no clients are connected and identified. It can be modified statically with the aid of the “TraceLev” key in the [Global] section of the server configuration file called “SofrelOPCServer.ini ”, which resides in the “OPC” subfolder of the PCWin installation folder. Any such modifications only take effect when the SofrelOPCServer is restarted. This parameter can also be modified dynamically with the aid of OPC component “SYSTEM/TRACELEV”. This type of modification takes effect immediately and is stored in the server configuration file. The default value of trace levels is 0, which corresponds to no trace. These traces are sent by default to an instance of the XS_CSuiviApp.exe PCWin application. The OPC server automatically starts this program when a trace is requested. It automatically stops XS_CSuiviApp.exe when it ends, which causes the monitoring window to close. The can however close this monitoring window at any time, in which case the traces are sent to the debugger controlling execution of the SofrelOPCServer via the OutputDebugString function (if the debugger is running). The monitoring window can be reopened by modifying the server’s trace level. Trace level changes in an existing monitoring window reuse the same window. However, only traces of the new level are sent to the window when levels change. Trace messages are formatted as follows: Client: date time function[line]: (SUCC|ERR)[result]{ : message} Optional message components are surrounded by square brackets. The expressions in brackets are syntax groups. The ‘|’ operator indicates a choice between two possible expressions. The date format is DD-MM-YYYY and the time format is HH :MM :SS.SSS. Function names are explicit and take into the complete name space in which the function is defined (class or namespace name). The result is returned either with the “SUCC” keyword if the operation was successful or with the “ERR” keyword. The full error message is surrounded by curly braces after the result. If the error has no description, its full error code is returned in hexadecimal format. The “message” part is optional and only appears for certain trace messages. It is used more particularly for messages of the CALLS category to indicate the list of parameters and the function’s return value. Activity traces of various different clients are differentiated by prefixing them with the client name whenever possible. The name is supplied by the client when it calls IOPCCommon::SetClientName, or a name automatically generated by the server using the ID the client supplies in “SYSTEM/CLIENTID”. However, for the execution of internal server functions (timer recall and PCWin functions), for which there is no client as such, the name cannot be that of a client. Internal operation traces are therefore identified as “SofrelOPCServer”.
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2.3 Browser management The OPC server handles system configuration through a data tree structure called “browser”. The browser handles the OPC interfaces and also acts as a level-2 cache, PCWin itself being a level-1 cache for station variables. The browser is created when the server starts and is initialized with data supplied by PCWin. It is then kept synchronized with the PCWin configuration through the notifications it receives when: ‚
a datapoint is added to PCWin (variable, station or group of stations) ;
‚
a datapoint is deleted (variable, station or group of stations) ;
‚
a datapoint is renamed (variable, station or group of stations) ;
‚
a datapoint is modified (change in the value of any variable’s attribute).
2.4 Managing time-stamped values Time-stamped values are accessible via OPC item “variable/HVALUE”. An alternative way of accessing them is via OPC item “variable/VALUE” thanks to configuration parameter HISTMIX, which can equal 0 or 1. Its default value is 0, which allows time-stamp values to be read via OPC item HVALUE. If however its value is forced to 1, time-stamped values are transferred to OPC item VALUE and HVALUE is then invalid. The value of the HISTMIX parameter can then be statically modified with the aid of the “HistMix“ key in the [Reprise] section of the server configuration file. SofrelOPCServer must be restarted for such changes to take effect. It can also be dynamically modified with the aid of OPC item “SYSTEM/HISTMIX”. This type of modification takes effect immediately and is saved in the server configuration file. To handle the case of clients that cannot receive several history values in a single notification, successive notifications can be issued separated by a time delay. It can be checked with the HISTRATE parameter in the [Reprise] section of the server configuration file. This parameter can also be dynamically modified with the aid of item OPC “SYSTEM/HISTRATE”. Each group rounds up the specified time delay to the next value by a multiple of its update rate. A nil value corresponds to burst operation, in which all history values are transferred in a single notification. HVALUE history values are only notified when new values are available in the PCWin archives. As a result, these items are flagged OPC_QUALITY_BAD when a client logs on, and no value must be returned to it. To allow initial notification of the last reported value for the clients who so desire, the HSTARTNOTIFY parameter has been added to the [Global] section of the server. When it equals 1, the last reported value for a client is notified for each subscription to a HVALUE item. In such cases the client program has to handle any duplicate history values it receives. This parameter is also dynamically accessible via item SYSTEM/HSTARTNOTIFY.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.5 Managing archives History and report data for the PCWin archive server can be accessed via specific station variable attributes. OPC items can be defined for these attributes using the “variable/attribute” syntax. Attribute names vary according to variable type (TC, RC, TM, etc…). A timer controls periodic polling of the archive server to retrieve the data. Polling time is determined by the HISTPER configuration parameter, which is expressed in minutes (its default value is 5). It can be statically modified under “HistPer” in the [Reprise] section of the server configuration file. This type of modification only takes effect when the server restarts, however, it can be automatically modified by means of OPC item “SYSTEM/HISTPER”. Systematic polling of the archive server can be deactivated by setting HISTPOLL parameter in the [Global] section to 0, in which case polling of clients only occurs if the last date of communication with the station postdates the client’s the last station polling date. This improvement means that station calls are only performed when they are necessary. If the HISTPOLL parameter is set to 1, polling systematically occurs when the timer runs out. In such cases the station does not have to be called to retrieve new histories. This optimization is activated by default. From version 2.0.23, the OPC server detects modifications in the PCWin database and retrieves the data at each period if there has been a write operation. Parameter HISPOLL has no further purpose and is ignored. The rate of returning report values is also controlled by system item “SYSTEM/HISTRATE”, which is described in the section dealing with time-stamped values. From version 2.0.34 onwards and in order to improve server performance, all items to view are broken down into sets. This breakdown into sets allows the server to provide faster notification for its OPC clients in the event of a very large configuration. The maximum number of items per set is defined in the [Global] section "Lot” parameter; the default value is 100 items. Furthermore, the report/history viewing alternation no longer exists; items are viewed independently of their type (history or summary).
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2.6 Multiple client management The SofrelOPCServer server accepts several simultaneous client connections. However, since the in-process version is dynamically linked to each executable using it, it can only handle clients in the same addressing space. The local server version on the other hand makes no distinction between clients, who are all located in different addressing spaces. A COPCServer object is created when clients log on. This object is only used for a particular client. However, server data are shared among all such objects. More particularly, there is only one instance of the browser per instance of the SofrelOPCServer server (in-process or executable). All modifications made by a client are therefore immediately taken into by the other clients. In particular, the values of system items (archive polling period, communication mode with PCWin stations, datapoint management via OPC item “variable/VALUE” and active trace level) are common to all clients. The only exception to this rule is OPC item “SYSTEM/CLIENTID”, which represents the client ID and is unique to each client. This item is therefore an attribute of the COPCServer class. Modification of this item by one of the groups is therefore acknowledged by all the groups the server has created. The groups of other server objects are not notified of this modification. The client can identify itself directly via the OPC item using the syntax “SYSTEM/CLIENTID(ID)”, where ID is the client number. Clients do not have to identify themselves to use the OPC server, in which case they are automatically assigned ID 0. Several clients can use the OPC server without being identified, but in such instances the SofrelOPCServer server cannot guarantee that all clients will receive all the notifications for time-stamped data. The recovery files used for each client are located in subfolder “OPC\n” in the PCWin installation folder, where “n” is the client ID. However, the configuration files for client 0 remain in subfolder “OPC” to remain compatible with version 1.0 of the SofrelOPCServer server. So it is important that clients systematically identify themselves via item “SYSTEM/CLIENTID” using the same ID, to ensure that history and report polling dates for client 0 are not transmitted to several clients. Client identification must occur within a specified time limit, according to the items added at the start of this group. The default timeout is 10 seconds, bit it can be modified in the server’s general configuration file. During the timeout, the COPCServer component disables notification mechanisms for all its groups, and historical data are not transmitted immediately. However, this timeout stops as soon as the client identifies itself, at which point all groups are re-enabled. It is also advisable for the client to record a name in the server via the IOPCCommon::SetClientName method. This name is used by the trace mechanism to identify the name under which traced calls are made. If the client fails to provide its name or is a “OPC 1.0a client”, the default name “Client n” is generated and used (“n” being the client ID). Furthermore, the generic name “SofrelOPCServer” is used for tracking processes not connected with client activity. Among other things, this concerns initialization processes and processes occurring during callbacks from PCWin and timers.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.7 Asynchronous communications management The SofrelOPCServer server handles asynchronous queries of the IOPCAsyncIO and IOPCAsyncIO2 interface b creating objects that describe asynchronous operations and placing them in a list of asynchronous operations to be performed. This list is maintained at the level of the group receiving the asynchronous query. Asynchronous operations stored in this list are then executed in the background when a timer callback function is called. Similarly, notifications of OPC items whose variables they reference have been modified are also performed asynchronously by the same timer’s callback function. The timer’s basic default interval is 100 ms, but this can be modified in parameter BASERATE in the [Global] section of the server configuration file. Asynchronous operations are however only performed every 100 server notifications, which therefore corresponds to a default interval of 1 second between two executions. For each asynchronous operation performed, a notification is sent to the client that issued the query. The notification uses the standard notification mechanism of the IDataObject OLE interface. Asynchronous operation objects are then deleted from the list of operations to be performed. By default, the server can store an arbitrary number of asynchronous queries awaiting execution. However, this behavior can be changed by setting a value for the “MaxIOPending” key in the configuration file. This key contains the maximum number of operations awaiting execution that the server can accept for each type of asynchronous operation (read, write or refresh). This key’s default value is 0, meaning there is no limit to the arbitrary number of operations.
2.8 OPC items The syntax for OPC items uses the paths in the browser’s tree structure to reference the attributes of the variables referenced by the items. The separator used in these paths is ‘/’ (forward slash). The root is not specified. The SYSTEM variable can be accessed by using the name “SYSTEM”, and the list of stations is accessed using the name “STATIONS”. The stations themselves are placed on the STATIONS branch and can be accessed by using the names specified in the PCWin configuration. The various attributes accessible in the different variables are referenced in the following sections.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.1
SYSTEM Variable The SYSTEM variable contains attributes providing access to the main configuration options of the SofrelOPCServer server. Among these items, only the SYSTEM/CLIENTID item is distinct for each COPCServer component. Name HISTMIX
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
When this flag is set to TRUE, time-stamped data can be transferred to the VALUE field instead of the HVALUE field of stations variables.
Name HISTPER
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter indicates the polling time for PCWin archives for retrieving report and history data. It is expressed in minutes, its default value being 5. It cannot be set to 0. Name HISTINT
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter is a number of days before the current date and determines the start date for report and history data searches, the end date being the current date. Its default value is 7 days. This parameter is ignored during subsequent searches, and the start date is the date of the last value retrieved by the previous search. Name HISTRATE
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter indicates the rate at which history and report values are retrieved (one notification per value). Its value corresponds to a number of milliseconds between each notification. Its default value is nil, corresponding to a burst mode of data retrieval. In this mode, all datapoints are retrieved in a single notification. This mode is more efficient, but is not ed by all clients. Name HSTARTNOTIFY
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter allows the last notified value for a client to be retrieved when subscribing to an item of the HVALUE type. Its default value is 0, meaning no initial notification. Name RUNNING
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines whether no not PCWin is active. Name STOP
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute value to TRUE forces PCWin to stop.
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Name GO
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute value to TRUE starts PCWin. Name COMIMM
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter puts PCWin in immediate or deferred communication mode with regard to stations for transmitting setpoints. Name TRACELEV
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter represents the trace level used by the OPC server. Trace level 0 means “no trace”. Changing trace level displays a PCWIN monitoring server window if it is not already open or has been closed. Name CLIENTID
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute lets a client identify itself at the level of the OPC server. Clients must ensure that their ID is unique at server level. Furthermore, they must reuse the same ID for each session. This ID allows the server to determine resume dates for report and history data polling.
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2.8.2
Station parameters Station parameters are common to all the stations. Name
Type
Attribute
CALL
VT_BOOL
OPC_WRITEABLE
Setting this attribute value to TRUE forces PCWin to poll a station. Name
Type
Attribute
HOLDCOMM
VT_I4
OPC_READABLE, OPC_WRITEABLE
If this attribute is written, the station is polled continuously for the specified period of time if the station is not in communication, or modifies the time period if the station is already in communication. The unit in question is the second. Name STOPCOMM
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute’s value to TRUE stops in advance current communications initiated via the HOLDCOMM or CALL attribute, by an mechanism internal to PCWIN or by the station itself on a spontaneous call. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines the validity of a station. A station is invalid when so configured in PCWin or when PCWin is not running. The data of an invalid station is invalid, which means that the last known values in the OPC server’s cache are returned instead. Name ACK
Type VT_UI1
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter specifies the alarm acknowledgement management rule, its possible values being:
‚ ‚ ‚
0: no acknowledgement management; 1: acknowledgement; 2: no acknowledgement.
The writing of this parameter is only taken into for the current communication. Name CODATE
Type VT_BSTR
Attribute OPC_READABLE
This parameter determines the last date on which a station was polled. This date is returned by PCWin when it finishes polling the station. It is formatted in accordance with the date-formatting conventions for Windows s.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3
Station variables Station variable attributes vary according to the type of variable. They are described for each type in the following sections:
2.8.3.1 TS-type variables Name VALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides access to the variable’s value. Name HVALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute reads the last time-stamped value for this variable. Name EVTCOUNT
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the daily report event timer. Name TIMER
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the daily report’s time meter. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others being retrieved from the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the validity of the variable. A variable in invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last time the value was updated in PCWin (whether or not it was set in the operator dialog box, by the communication or by the OPC client). This date is updated further to any PCWin notification, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
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2.8.3.2
TC-type variables Name
VALUE
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute provides access to the value of the variable. Writing this item forces the related FORCED item to TRUE, and transmits if COMIMM = TRUE (or stores it in the PCWin’s buffer zone PCWin if COMIMM = FALSE). Name HVALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute reads the last time-stamped value for this variable. Name FORCED
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute indicates forcing of the TC setpoint. FALSE means that the setpoint is free, and TRUE means that it has been forced by the SCADA central station. Writing this item causes polling of the station if COMIMM = TRUE. Name SENDING
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines where any modifications made to this variable’s values will be sent. FALSE indicates that the target is PCWin and that the datapoint is handled internally, while TRUE indicates that the value will be sent to the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache.
Name TOSEND
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the state of setpoint transmission. Its possible values are as follows:
‚ ‚
FALSE for a setpoint sent to the RTU; TRUE for a setpoint awaiting transmission to the RTU.
Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
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2.8.3.3 RC-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE
This attribute provides access to the value of the variable. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name SECTION1
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the first section in the daily report. Name SECTION2
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the second section in the daily report. Name SECTION3
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the third section in the daily report. Name INDEX
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the counting index at the time of the daily report. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others are retrieved on the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
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2.8.3.4 TM-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE
This attribute provides access to the value of the variable. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name MINVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the minimum value of the daily report. Name AVGVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the average value of the daily report. Name MAXVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the maximum value of the daily report. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others are retrieved on the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
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2.8.3.5 RA-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute provides access to the value of the variable. Writing this item forces the related FORCED item to TRUE, and transmits if COMIMM = TRUE or stores it in the PCWin’s buffer zone PCWin if COMIMM = FALSE. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name FORCED
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute indicates forcing of the RA set point. FALSE means the setpoint is free, and TRUE indicates that it has been forced by the SCADA central station. Writing this item causing polling of the station if COMIMM = TRUE. Name SENDING
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines where any modifications made to this variable’s values will be sent. FALSE means that it will be sent to PCWin and handled internally, and TRUE means that the value will be sent to the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the variable’s validity. A variable in invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name TOSEND
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the state of setpoint transmission. Its possible values are as follows:
‚ ‚
FALSE for a setpoint sent to the RTU; TRUE for a setpoint awaiting transmission to the RTU. Name
UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
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2.8.4
Station group parameters Stations group parameters are common to all station groups. Name CALL
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
Writing TRUE to the value of this attribute forces PCWin to poll a group of stations.
Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter determines the validity of a group of stations. A group of stations is invalid when so configured in PCWin or when PCWin is not running. The validity of a group can be modified by OPC. When a group of stations is declared invalid, all current and pending automatic and periodic polling is deactivated. When a group is validated, automatic and periodic polling is validated.
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3. OPERATING CONDITIONS 3.1 Operating environment The SofrelOPCServer server works with any client compatible with the OPC 2.0 standard. It is supplied both in the form of a DLL file containing the server management components and as a standalone executable file. These COM components must be ed in the registry before being used. This must be done using the REGSVR32.EXE utility for the DLL server, specifying the “/RegServer” option on the command line for the EXE server. The InProc (DLL) server is ed under the name SofrelOPCServer. The Local (EXE) server is ed under the name SofrelOPCServerExe.
3.2 Configuration file 3.2.1 Main configuration file The SofrelOPCServer server uses configuration file “SofrelOPCServer.ini”, which resides in the “OPC” subfolder of PCWin’s installation folder. This configuration file contains the server’s general persistent data. Its syntax is as follows:
[Reprise] HistMix = 0 HistPer = 5 HistInt
= 7
HistRate = 0 ComImm
= 0
[Global] BaseRate = 100 StartDelay = 10 MaxIOPending = 0 TraceLev = 0 AlwaysNotify = 0 Lot=100
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The [Reprise] section contains the “HistMix”, “HistPer”, “HistInt”, “HistRate” and “ComImm” keys. ‚
“HistMix” key is a DWORD-type key taking values 0 or 1. When set to 1, it transits timestamped values for a datapoint to OPC VALUE items instead of transmitting them to HVALUE items.
‚
“HistPer” key is a DWORD-type key containing PCWin archive polling times in minutes for histories and reports. Its default value is 5 minutes. the value 0 is prohibited and cannot be used.
‚
“HistInt” key is a DWORD-type key containing the number of days to subtract from the current date to determine the first polling date when the server is first started. Its default value is 7 days.
‚
“HistRate” key is a DWORD-type key containing the timeout in milliseconds between two notifications for the history and report values of a given item. Its default value is 0, corresponding to combined retrieval of all histories in a single notification (burst mode).
‚
“ComImm” key is a DWORD-type key that can be set to 0 or 1. Setting it to 1 forces PCWin to communicate with the stations immediately. Its default value is 0, which allows PCWin to defer communications with the stations and to group and process queries in sets.
NB:
all these keys can be dynamically modified using the OPC server’s “system” item. Such modifications take effect immediately and the new values are saved in the SofrelOPCServer.ini configuration file.
The [Global] section contains the “BaseRate”, “StartDelay”, “MaxIOPending”, “TraceLev” and “AlwaysNotify” keys. ‚
“BaseRate” key is a DWORD-type key. It expresses the base rate in seconds for the timer used to execute asynchronous operations and transmit histories. Its default value is 100 milliseconds.
‚
“StartDelay” key indicates the amount of time allowed for clients to identify themselves by means of the item OPC “SYSTEM/CLIENTID” before the first item notifications occur. It is expressed in seconds, its default value being ten.
‚
“MaxIOPending” sets the maximum number of operations pending execution for each type of asynchronous operation. Its default value is 0, which means there is no limit to the number of pending operations.
‚
“TraceLev” key is a DWORD-type key containing the trace levels used by the OPC server. Its default trace level value is 0, meaning no trace. This value can be dynamically modified with the aid of the “SYSTEM/TRACELEV” item.
‚
"AlwaysNotify" key is a BOOLEAN key; it determines the server’s behavior when optimizing the number of notifications for a VALUE item change. When this key is 0 (default value), the server makes a single notification for several simultaneous operations (subscription, synchronous or asynchronous read, refresh). When this key is 1, the server performs a notification for each operation.
‚
Optional "Lot" key is a DWORD key; it determines the number of items to process in a set when consulting the archiving server. Its default value is 100.
NB:
none of these keys (with the exception of “TraceLev”) can be dynamically modified by an OPC server item.
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Station configuration files The SofrelOPCServer server also uses an .ini file for each client and station declared in the PCWin configuration file; they each contain the dates of the last variable polling for the station and client in question. The structure of these configuration files is the same for all the clients. Station configuration files are grouped by client in subfolders in the server configuration folder. These folders are named using the client ID in OPC item “SYSTEM/CLIENTID” or using a default ID number. For client ID 0, the files are stored in the server configuration folder to ensure backward compatibility with the version 1.0 server. Each “.ini” file contains a section for each station variable. The keys of these sections are respectively named according to the various attributes of these values as they appear in the syntax for OPC items. These are string-type keys containing the value of the last date on which the attribute was queried. The date format used is the Windows DATE.
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LACROIX Sofrel 2, rue du Plessis 35 770 VERN SUR SEICHE Telephone: 02 . 99 . 04 . 89 . 00
Fax: 02 . 99 . 04 89 . 01
SOFREL PCWin - OPC Server Function Specifications File
Reference........ : PCW-DSF_OPCV232-ag.doc Version ........... : V 2.34 Date ................ : 18 June 2007 Classification.... : Public
By.................. : Gilles ROUAULT
Approved by........ : MB
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LIST OF UPDATES First version Previous version
: 1.10 : 2.33
Date: 09 / 07 / 98 Date: 26 / 10 / 05
DESCRIPTION OF MODIFICATIONS Date
Name
Paragraphs
Reasons V 1.11 :
24/9/99
GR
References
Added reference [1] and renumbered
1.1
Added reference [1]
2.3.2.1
New paragraph
2.3.2.2
New paragraph
2.3.2.3
New paragraph V 1.12 :
22/10/99
LL
2.3.2.1
Modified description of the ACK item
GR
2.3.2.1
Added explanation on HOLDCOMM and STOPCOMM Added SENDING item and modified description of ACQUISITION V2.10
05/05/00
LL
14/11/00
LL
Document entirely overhauled document V2.11 2.2
Added trace levels; TraceLev in [Global] section
2.4, 2.5 et 2.8.1
Description of HISTRATE item
2.7
Added BASERATE parameter
2.8.3
Details on UPDATE item
2.8.3.3
Description of SECTION3 corrected V2.12
09/03/01
LL
2.4
Description of functioning of HSTARTNOTIFY for handling initial history values.
2.5
Description of functioning of HISTPOLL for handling stampdated value searches. V2.13
11/12/03
LL
2.5
Description of the functioning of history polling from V2.0.23. V2.30
02/03/04
PL
2.8, 2.3
7/04/05
LH
2.2
Added groups of stations from server version 2.0.30. V2.32 Addition of a level of traces operator to replace the traces meter of reference from server version 2.0.32.
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V2.33 SG
Change of document number to match server version. V2.34
24/04/07
LH / SF
3.2.1
Addition of the AlwaysNotify key
2.8
New pagination
2.3
Deletion of the paragraph covering OCCibleNotification mechanism implementation
2
Addition of a general architecture diagram
2.5
Archive management: the archive viewing summary/history alternation no longer exists. Each item is dealt with according to type (history or summary). Addition of the description of the new viewing mode implemented from this version 2.0.34.
3.2.1
Addition of the “Lot” key
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REFERENCES
[1] OPC Data Access Custom Interface Specification V1.0a (OPCDA10A.doc) [2]: OPC: OLE for Process Control: a communication standard based on OLE/COM technology, which is the new data exchange method between MSWindows applications.
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CONTENTS
1. INTRODUCTION
7
1.1 Purpose
7
1.2 Reference documents
7
1.3 Terminology and abbreviations
7
1.3.1 Terminology 1.3.2 Abbreviations
2. DESCRIPTION OF FUNCTIONALITIES
7 7
8
2.1 Starting PCWin
8
2.2 Trace management
8
2.3 Browser management
10
2.4 Managing time-stamped values
10
2.5 Managing archives
11
2.6 Multiple client management
12
2.7 Asynchronous communications management
13
2.8 OPC items
13
2.8.1 2.8.2 2.8.3 2.8.4
SYSTEM Variable Station parameters Station variables Station group parameters
3. OPERATING CONDITIONS
14 16 17 22
23
3.1 Operating environment
23
3.2 Configuration file
23
3.2.1 Main configuration file 3.2.2 Station configuration files
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1. INTRODUCTION 1.1 Purpose This document presents OPC server implementation specifications based on SOFREL’s PCWin software. The server implements the functionalities of the OPC 2.0 standard.
1.2 Reference documents Reference OPC standard
Title Data Access Custom Interface Standard v2.0 June 19, 1998
External SOFREL Document
Interfacing PCWin with a OPC v1.70 server
1.3 Terminology and abbreviations 1.3.1 Terminology PCWin is a remote monitoring and control software package for SCADA central stations developed by SOFREL. It provides data access to SOFREL remote terminal units and centralizes the data on the SCADA central station. PCWin can be controlled via a PLC based on OLE Automation. The PLC is used in PCWin’s client software.
1.3.2 Abbreviations Not applicable.
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2. DESCRIPTION OF FUNCTIONALITIES The functionalities available in the SofrelOPCServer server allow standardized access to the data in Sofrel supervisory control stations and the PCWin software package. Data access is based on COM/OLE technology and occurs via OPC 2.0 interfaces. Optional interfaces are only implemented if they can be of any use in a server running PCWin. The SofrelOPCServer server is available in two versions, which are functionally identical with regard to the OPC 2.0 standard. The first version is an in-process server (implemented though a dynamic library), and the second version is a local or remote server (implemented in an executable). Sofrel OPC Server
PCWin
OPC
OPC Client
2.1 Starting PCWin The SofrelOPCServer server starts PCWin when first connecting, if PCWin is not already running. It does not shut down PCWin when it stops, because it is not necessarily the only PCWin . However, it is possible to force PCWin to stop using OPC function “SYSTEM/STOP”. When PCWin is not running, an OPC client can restart it using the “SYSTEM/GO” function.
2.2 Trace management The SofrelOPCServer server transmits traces during the main operations that occur while it is running. The traces issued are classified by trace level. Trace levels represent trace category groups, which can all be independently activated through bit combinations. The existing categories of traces are listed in the following table: Index of bit in level 0
1
Prefix used for this Active trace category category IN/OUT Input/output trace for functions
1
2
ACCESS
Accessor call trace (values read and written)
2
4
CYCLE
Trace of object lifecycle destruction)
3
8
ALGO
Trace of algorithm usage
4
16
CALLS
Trace of function results (parameters and results of the call)
5
32
OLE I/O
Input/Output trace OLE interface methods
6
64
OLE CALL
OLE interface methods result trace (parameters and results of the call)
7
128
SUIVIOP
Operator-level trace (functional monitoring with the names of items OPC in light)
NO TRACE
Reserved
8 to 31
Trace level
events (construction
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and
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The prefix is a character string placed prefixing the trace message proper identifying the category the message trace. The trace level is a global operating parameter of the SofrelOPCServer, which is defined even when no clients are connected and identified. It can be modified statically with the aid of the “TraceLev” key in the [Global] section of the server configuration file called “SofrelOPCServer.ini ”, which resides in the “OPC” subfolder of the PCWin installation folder. Any such modifications only take effect when the SofrelOPCServer is restarted. This parameter can also be modified dynamically with the aid of OPC component “SYSTEM/TRACELEV”. This type of modification takes effect immediately and is stored in the server configuration file. The default value of trace levels is 0, which corresponds to no trace. These traces are sent by default to an instance of the XS_CSuiviApp.exe PCWin application. The OPC server automatically starts this program when a trace is requested. It automatically stops XS_CSuiviApp.exe when it ends, which causes the monitoring window to close. The can however close this monitoring window at any time, in which case the traces are sent to the debugger controlling execution of the SofrelOPCServer via the OutputDebugString function (if the debugger is running). The monitoring window can be reopened by modifying the server’s trace level. Trace level changes in an existing monitoring window reuse the same window. However, only traces of the new level are sent to the window when levels change. Trace messages are formatted as follows: Client: date time function[line]: (SUCC|ERR)[result]{ : message} Optional message components are surrounded by square brackets. The expressions in brackets are syntax groups. The ‘|’ operator indicates a choice between two possible expressions. The date format is DD-MM-YYYY and the time format is HH :MM :SS.SSS. Function names are explicit and take into the complete name space in which the function is defined (class or namespace name). The result is returned either with the “SUCC” keyword if the operation was successful or with the “ERR” keyword. The full error message is surrounded by curly braces after the result. If the error has no description, its full error code is returned in hexadecimal format. The “message” part is optional and only appears for certain trace messages. It is used more particularly for messages of the CALLS category to indicate the list of parameters and the function’s return value. Activity traces of various different clients are differentiated by prefixing them with the client name whenever possible. The name is supplied by the client when it calls IOPCCommon::SetClientName, or a name automatically generated by the server using the ID the client supplies in “SYSTEM/CLIENTID”. However, for the execution of internal server functions (timer recall and PCWin functions), for which there is no client as such, the name cannot be that of a client. Internal operation traces are therefore identified as “SofrelOPCServer”.
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2.3 Browser management The OPC server handles system configuration through a data tree structure called “browser”. The browser handles the OPC interfaces and also acts as a level-2 cache, PCWin itself being a level-1 cache for station variables. The browser is created when the server starts and is initialized with data supplied by PCWin. It is then kept synchronized with the PCWin configuration through the notifications it receives when: ‚
a datapoint is added to PCWin (variable, station or group of stations) ;
‚
a datapoint is deleted (variable, station or group of stations) ;
‚
a datapoint is renamed (variable, station or group of stations) ;
‚
a datapoint is modified (change in the value of any variable’s attribute).
2.4 Managing time-stamped values Time-stamped values are accessible via OPC item “variable/HVALUE”. An alternative way of accessing them is via OPC item “variable/VALUE” thanks to configuration parameter HISTMIX, which can equal 0 or 1. Its default value is 0, which allows time-stamp values to be read via OPC item HVALUE. If however its value is forced to 1, time-stamped values are transferred to OPC item VALUE and HVALUE is then invalid. The value of the HISTMIX parameter can then be statically modified with the aid of the “HistMix“ key in the [Reprise] section of the server configuration file. SofrelOPCServer must be restarted for such changes to take effect. It can also be dynamically modified with the aid of OPC item “SYSTEM/HISTMIX”. This type of modification takes effect immediately and is saved in the server configuration file. To handle the case of clients that cannot receive several history values in a single notification, successive notifications can be issued separated by a time delay. It can be checked with the HISTRATE parameter in the [Reprise] section of the server configuration file. This parameter can also be dynamically modified with the aid of item OPC “SYSTEM/HISTRATE”. Each group rounds up the specified time delay to the next value by a multiple of its update rate. A nil value corresponds to burst operation, in which all history values are transferred in a single notification. HVALUE history values are only notified when new values are available in the PCWin archives. As a result, these items are flagged OPC_QUALITY_BAD when a client logs on, and no value must be returned to it. To allow initial notification of the last reported value for the clients who so desire, the HSTARTNOTIFY parameter has been added to the [Global] section of the server. When it equals 1, the last reported value for a client is notified for each subscription to a HVALUE item. In such cases the client program has to handle any duplicate history values it receives. This parameter is also dynamically accessible via item SYSTEM/HSTARTNOTIFY.
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2.5 Managing archives History and report data for the PCWin archive server can be accessed via specific station variable attributes. OPC items can be defined for these attributes using the “variable/attribute” syntax. Attribute names vary according to variable type (TC, RC, TM, etc…). A timer controls periodic polling of the archive server to retrieve the data. Polling time is determined by the HISTPER configuration parameter, which is expressed in minutes (its default value is 5). It can be statically modified under “HistPer” in the [Reprise] section of the server configuration file. This type of modification only takes effect when the server restarts, however, it can be automatically modified by means of OPC item “SYSTEM/HISTPER”. Systematic polling of the archive server can be deactivated by setting HISTPOLL parameter in the [Global] section to 0, in which case polling of clients only occurs if the last date of communication with the station postdates the client’s the last station polling date. This improvement means that station calls are only performed when they are necessary. If the HISTPOLL parameter is set to 1, polling systematically occurs when the timer runs out. In such cases the station does not have to be called to retrieve new histories. This optimization is activated by default. From version 2.0.23, the OPC server detects modifications in the PCWin database and retrieves the data at each period if there has been a write operation. Parameter HISPOLL has no further purpose and is ignored. The rate of returning report values is also controlled by system item “SYSTEM/HISTRATE”, which is described in the section dealing with time-stamped values. From version 2.0.34 onwards and in order to improve server performance, all items to view are broken down into sets. This breakdown into sets allows the server to provide faster notification for its OPC clients in the event of a very large configuration. The maximum number of items per set is defined in the [Global] section "Lot” parameter; the default value is 100 items. Furthermore, the report/history viewing alternation no longer exists; items are viewed independently of their type (history or summary).
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2.6 Multiple client management The SofrelOPCServer server accepts several simultaneous client connections. However, since the in-process version is dynamically linked to each executable using it, it can only handle clients in the same addressing space. The local server version on the other hand makes no distinction between clients, who are all located in different addressing spaces. A COPCServer object is created when clients log on. This object is only used for a particular client. However, server data are shared among all such objects. More particularly, there is only one instance of the browser per instance of the SofrelOPCServer server (in-process or executable). All modifications made by a client are therefore immediately taken into by the other clients. In particular, the values of system items (archive polling period, communication mode with PCWin stations, datapoint management via OPC item “variable/VALUE” and active trace level) are common to all clients. The only exception to this rule is OPC item “SYSTEM/CLIENTID”, which represents the client ID and is unique to each client. This item is therefore an attribute of the COPCServer class. Modification of this item by one of the groups is therefore acknowledged by all the groups the server has created. The groups of other server objects are not notified of this modification. The client can identify itself directly via the OPC item using the syntax “SYSTEM/CLIENTID(ID)”, where ID is the client number. Clients do not have to identify themselves to use the OPC server, in which case they are automatically assigned ID 0. Several clients can use the OPC server without being identified, but in such instances the SofrelOPCServer server cannot guarantee that all clients will receive all the notifications for time-stamped data. The recovery files used for each client are located in subfolder “OPC\n” in the PCWin installation folder, where “n” is the client ID. However, the configuration files for client 0 remain in subfolder “OPC” to remain compatible with version 1.0 of the SofrelOPCServer server. So it is important that clients systematically identify themselves via item “SYSTEM/CLIENTID” using the same ID, to ensure that history and report polling dates for client 0 are not transmitted to several clients. Client identification must occur within a specified time limit, according to the items added at the start of this group. The default timeout is 10 seconds, bit it can be modified in the server’s general configuration file. During the timeout, the COPCServer component disables notification mechanisms for all its groups, and historical data are not transmitted immediately. However, this timeout stops as soon as the client identifies itself, at which point all groups are re-enabled. It is also advisable for the client to record a name in the server via the IOPCCommon::SetClientName method. This name is used by the trace mechanism to identify the name under which traced calls are made. If the client fails to provide its name or is a “OPC 1.0a client”, the default name “Client n” is generated and used (“n” being the client ID). Furthermore, the generic name “SofrelOPCServer” is used for tracking processes not connected with client activity. Among other things, this concerns initialization processes and processes occurring during callbacks from PCWin and timers.
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2.7 Asynchronous communications management The SofrelOPCServer server handles asynchronous queries of the IOPCAsyncIO and IOPCAsyncIO2 interface b creating objects that describe asynchronous operations and placing them in a list of asynchronous operations to be performed. This list is maintained at the level of the group receiving the asynchronous query. Asynchronous operations stored in this list are then executed in the background when a timer callback function is called. Similarly, notifications of OPC items whose variables they reference have been modified are also performed asynchronously by the same timer’s callback function. The timer’s basic default interval is 100 ms, but this can be modified in parameter BASERATE in the [Global] section of the server configuration file. Asynchronous operations are however only performed every 100 server notifications, which therefore corresponds to a default interval of 1 second between two executions. For each asynchronous operation performed, a notification is sent to the client that issued the query. The notification uses the standard notification mechanism of the IDataObject OLE interface. Asynchronous operation objects are then deleted from the list of operations to be performed. By default, the server can store an arbitrary number of asynchronous queries awaiting execution. However, this behavior can be changed by setting a value for the “MaxIOPending” key in the configuration file. This key contains the maximum number of operations awaiting execution that the server can accept for each type of asynchronous operation (read, write or refresh). This key’s default value is 0, meaning there is no limit to the arbitrary number of operations.
2.8 OPC items The syntax for OPC items uses the paths in the browser’s tree structure to reference the attributes of the variables referenced by the items. The separator used in these paths is ‘/’ (forward slash). The root is not specified. The SYSTEM variable can be accessed by using the name “SYSTEM”, and the list of stations is accessed using the name “STATIONS”. The stations themselves are placed on the STATIONS branch and can be accessed by using the names specified in the PCWin configuration. The various attributes accessible in the different variables are referenced in the following sections.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.1
SYSTEM Variable The SYSTEM variable contains attributes providing access to the main configuration options of the SofrelOPCServer server. Among these items, only the SYSTEM/CLIENTID item is distinct for each COPCServer component. Name HISTMIX
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
When this flag is set to TRUE, time-stamped data can be transferred to the VALUE field instead of the HVALUE field of stations variables.
Name HISTPER
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter indicates the polling time for PCWin archives for retrieving report and history data. It is expressed in minutes, its default value being 5. It cannot be set to 0. Name HISTINT
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter is a number of days before the current date and determines the start date for report and history data searches, the end date being the current date. Its default value is 7 days. This parameter is ignored during subsequent searches, and the start date is the date of the last value retrieved by the previous search. Name HISTRATE
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter indicates the rate at which history and report values are retrieved (one notification per value). Its value corresponds to a number of milliseconds between each notification. Its default value is nil, corresponding to a burst mode of data retrieval. In this mode, all datapoints are retrieved in a single notification. This mode is more efficient, but is not ed by all clients. Name HSTARTNOTIFY
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter allows the last notified value for a client to be retrieved when subscribing to an item of the HVALUE type. Its default value is 0, meaning no initial notification. Name RUNNING
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines whether no not PCWin is active. Name STOP
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute value to TRUE forces PCWin to stop.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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Name GO
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute value to TRUE starts PCWin. Name COMIMM
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter puts PCWin in immediate or deferred communication mode with regard to stations for transmitting setpoints. Name TRACELEV
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter represents the trace level used by the OPC server. Trace level 0 means “no trace”. Changing trace level displays a PCWIN monitoring server window if it is not already open or has been closed. Name CLIENTID
Type VT_I4
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute lets a client identify itself at the level of the OPC server. Clients must ensure that their ID is unique at server level. Furthermore, they must reuse the same ID for each session. This ID allows the server to determine resume dates for report and history data polling.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.2
Station parameters Station parameters are common to all the stations. Name
Type
Attribute
CALL
VT_BOOL
OPC_WRITEABLE
Setting this attribute value to TRUE forces PCWin to poll a station. Name
Type
Attribute
HOLDCOMM
VT_I4
OPC_READABLE, OPC_WRITEABLE
If this attribute is written, the station is polled continuously for the specified period of time if the station is not in communication, or modifies the time period if the station is already in communication. The unit in question is the second. Name STOPCOMM
Type VT_BOOL
Attribute OPC_WRITEABLE
Setting this attribute’s value to TRUE stops in advance current communications initiated via the HOLDCOMM or CALL attribute, by an mechanism internal to PCWIN or by the station itself on a spontaneous call. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines the validity of a station. A station is invalid when so configured in PCWin or when PCWin is not running. The data of an invalid station is invalid, which means that the last known values in the OPC server’s cache are returned instead. Name ACK
Type VT_UI1
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter specifies the alarm acknowledgement management rule, its possible values being:
‚ ‚ ‚
0: no acknowledgement management; 1: acknowledgement; 2: no acknowledgement.
The writing of this parameter is only taken into for the current communication. Name CODATE
Type VT_BSTR
Attribute OPC_READABLE
This parameter determines the last date on which a station was polled. This date is returned by PCWin when it finishes polling the station. It is formatted in accordance with the date-formatting conventions for Windows s.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3
Station variables Station variable attributes vary according to the type of variable. They are described for each type in the following sections:
2.8.3.1 TS-type variables Name VALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides access to the variable’s value. Name HVALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute reads the last time-stamped value for this variable. Name EVTCOUNT
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the daily report event timer. Name TIMER
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the daily report’s time meter. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others being retrieved from the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the validity of the variable. A variable in invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last time the value was updated in PCWin (whether or not it was set in the operator dialog box, by the communication or by the OPC client). This date is updated further to any PCWin notification, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3.2
TC-type variables Name
VALUE
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute provides access to the value of the variable. Writing this item forces the related FORCED item to TRUE, and transmits if COMIMM = TRUE (or stores it in the PCWin’s buffer zone PCWin if COMIMM = FALSE). Name HVALUE
Type VT_BOOL
Attribute OPC_READABLE
This attribute reads the last time-stamped value for this variable. Name FORCED
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute indicates forcing of the TC setpoint. FALSE means that the setpoint is free, and TRUE means that it has been forced by the SCADA central station. Writing this item causes polling of the station if COMIMM = TRUE. Name SENDING
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines where any modifications made to this variable’s values will be sent. FALSE indicates that the target is PCWin and that the datapoint is handled internally, while TRUE indicates that the value will be sent to the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache.
Name TOSEND
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the state of setpoint transmission. Its possible values are as follows:
‚ ‚
FALSE for a setpoint sent to the RTU; TRUE for a setpoint awaiting transmission to the RTU.
Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3.3 RC-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE
This attribute provides access to the value of the variable. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name SECTION1
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the first section in the daily report. Name SECTION2
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the second section in the daily report. Name SECTION3
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the value of the third section in the daily report. Name INDEX
Type VT_R8
Attribute OPC_READABLE
This attribute gives the value of the counting index at the time of the daily report. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others are retrieved on the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3.4 TM-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE
This attribute provides access to the value of the variable. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name MINVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the minimum value of the daily report. Name AVGVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the average value of the daily report. Name MAXVAL
Type VT_R8
Attribute OPC_READABLE
This attribute indicates the maximum value of the daily report. Name ACQUISITION
Type VT_BOOL
Attribute OPC_READABLE
This attribute determines the origin of the value. Variables with this parameter set to FALSE are generated by PCWin, the others are retrieved on the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute provides the validity of the variable. A variable is invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.3.5 RA-type variables Name VALUE
Type VT_R8
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute provides access to the value of the variable. Writing this item forces the related FORCED item to TRUE, and transmits if COMIMM = TRUE or stores it in the PCWin’s buffer zone PCWin if COMIMM = FALSE. Name HVALUE
Type VT_R8
Attribute OPC_READABLE
This attribute reads the last time-stamped value for the variable. Name FORCED
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This attribute indicates forcing of the RA set point. FALSE means the setpoint is free, and TRUE indicates that it has been forced by the SCADA central station. Writing this item causing polling of the station if COMIMM = TRUE. Name SENDING
Type VT_BOOL
Attribute OPC_READABLE
This parameter determines where any modifications made to this variable’s values will be sent. FALSE means that it will be sent to PCWin and handled internally, and TRUE means that the value will be sent to the station. Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the variable’s validity. A variable in invalid when so configured in PCWin or when PCWin is not running. The values returned by invalid variables are those stored in the browser’s cache. Name TOSEND
Type VT_BOOL
Attribute OPC_READABLE
This attribute indicates the state of setpoint transmission. Its possible values are as follows:
‚ ‚
FALSE for a setpoint sent to the RTU; TRUE for a setpoint awaiting transmission to the RTU. Name
UPDATE
Type VT_BSTR
Attribute OPC_READABLE
This attribute determines the last update of the value in PCWin (whether or not it was set in the PCWin operator dialog box, by the communication or the OPC client). This date is updated further to PCWin notifications, even if the value in question has not changed. This item therefore qualifies the value’s validity irrespective of bandwidth mechanisms. The format used for this date complies with the formatting conventions for the currently logged on to Windows.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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2.8.4
Station group parameters Stations group parameters are common to all station groups. Name CALL
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
Writing TRUE to the value of this attribute forces PCWin to poll a group of stations.
Name VALIDITY
Type VT_BOOL
Attribute OPC_READABLE, OPC_WRITEABLE
This parameter determines the validity of a group of stations. A group of stations is invalid when so configured in PCWin or when PCWin is not running. The validity of a group can be modified by OPC. When a group of stations is declared invalid, all current and pending automatic and periodic polling is deactivated. When a group is validated, automatic and periodic polling is validated.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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3. OPERATING CONDITIONS 3.1 Operating environment The SofrelOPCServer server works with any client compatible with the OPC 2.0 standard. It is supplied both in the form of a DLL file containing the server management components and as a standalone executable file. These COM components must be ed in the registry before being used. This must be done using the REGSVR32.EXE utility for the DLL server, specifying the “/RegServer” option on the command line for the EXE server. The InProc (DLL) server is ed under the name SofrelOPCServer. The Local (EXE) server is ed under the name SofrelOPCServerExe.
3.2 Configuration file 3.2.1 Main configuration file The SofrelOPCServer server uses configuration file “SofrelOPCServer.ini”, which resides in the “OPC” subfolder of PCWin’s installation folder. This configuration file contains the server’s general persistent data. Its syntax is as follows:
[Reprise] HistMix = 0 HistPer = 5 HistInt
= 7
HistRate = 0 ComImm
= 0
[Global] BaseRate = 100 StartDelay = 10 MaxIOPending = 0 TraceLev = 0 AlwaysNotify = 0 Lot=100
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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The [Reprise] section contains the “HistMix”, “HistPer”, “HistInt”, “HistRate” and “ComImm” keys. ‚
“HistMix” key is a DWORD-type key taking values 0 or 1. When set to 1, it transits timestamped values for a datapoint to OPC VALUE items instead of transmitting them to HVALUE items.
‚
“HistPer” key is a DWORD-type key containing PCWin archive polling times in minutes for histories and reports. Its default value is 5 minutes. the value 0 is prohibited and cannot be used.
‚
“HistInt” key is a DWORD-type key containing the number of days to subtract from the current date to determine the first polling date when the server is first started. Its default value is 7 days.
‚
“HistRate” key is a DWORD-type key containing the timeout in milliseconds between two notifications for the history and report values of a given item. Its default value is 0, corresponding to combined retrieval of all histories in a single notification (burst mode).
‚
“ComImm” key is a DWORD-type key that can be set to 0 or 1. Setting it to 1 forces PCWin to communicate with the stations immediately. Its default value is 0, which allows PCWin to defer communications with the stations and to group and process queries in sets.
NB:
all these keys can be dynamically modified using the OPC server’s “system” item. Such modifications take effect immediately and the new values are saved in the SofrelOPCServer.ini configuration file.
The [Global] section contains the “BaseRate”, “StartDelay”, “MaxIOPending”, “TraceLev” and “AlwaysNotify” keys. ‚
“BaseRate” key is a DWORD-type key. It expresses the base rate in seconds for the timer used to execute asynchronous operations and transmit histories. Its default value is 100 milliseconds.
‚
“StartDelay” key indicates the amount of time allowed for clients to identify themselves by means of the item OPC “SYSTEM/CLIENTID” before the first item notifications occur. It is expressed in seconds, its default value being ten.
‚
“MaxIOPending” sets the maximum number of operations pending execution for each type of asynchronous operation. Its default value is 0, which means there is no limit to the number of pending operations.
‚
“TraceLev” key is a DWORD-type key containing the trace levels used by the OPC server. Its default trace level value is 0, meaning no trace. This value can be dynamically modified with the aid of the “SYSTEM/TRACELEV” item.
‚
"AlwaysNotify" key is a BOOLEAN key; it determines the server’s behavior when optimizing the number of notifications for a VALUE item change. When this key is 0 (default value), the server makes a single notification for several simultaneous operations (subscription, synchronous or asynchronous read, refresh). When this key is 1, the server performs a notification for each operation.
‚
Optional "Lot" key is a DWORD key; it determines the number of items to process in a set when consulting the archiving server. Its default value is 100.
NB:
none of these keys (with the exception of “TraceLev”) can be dynamically modified by an OPC server item.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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3.2.2
25
Station configuration files The SofrelOPCServer server also uses an .ini file for each client and station declared in the PCWin configuration file; they each contain the dates of the last variable polling for the station and client in question. The structure of these configuration files is the same for all the clients. Station configuration files are grouped by client in subfolders in the server configuration folder. These folders are named using the client ID in OPC item “SYSTEM/CLIENTID” or using a default ID number. For client ID 0, the files are stored in the server configuration folder to ensure backward compatibility with the version 1.0 server. Each “.ini” file contains a section for each station variable. The keys of these sections are respectively named according to the various attributes of these values as they appear in the syntax for OPC items. These are string-type keys containing the value of the last date on which the attribute was queried. The date format used is the Windows DATE.
This document is the property of LACROIX Sofrel and may not be disclosed to any third part without its written permission.
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