[OPC Simulation Server]
LicenseKey=Demo
ActiveConfig = 2

[Config 1]
Database=TpnServer.csv
Simulate=True
Scripts=0

[Config 2]
Database=Loopsim.csv
Simulate=True
Scripts=1
Script1=Scripts\LoopSim.vbs
Main1=LoopSim

[Config 3]
Database=ZCalc.csv
Simulate=True
Scripts=0

[Config 4]
Database=WellTest.csv
Simulate=True
Scripts=1
Script1=Scripts\WellTest.vbs
ScriptExecInterval1 = 5
Main1=WellTest

  Database=ZCalc.csv

Simulate This is the overall simulation On/Off switch that can be used to enable or disable simulation for all data items. The simulation switch can be set on from the main menu of the OPC Sim Server. Scripts This directive specifies the number of scripts for a simulation, e.g. Scripts=1. If the simulation does not use scripts, set Scripts=0 or omit the directive. ScriptX (X=1,2,3...) For each script, this directive specifies the name of the file containing the VB Script. For example: Script1=Scripts\LoopSim.vbs Script2=Scripts\PlantSim.vbs MainX (X=1,2,3...) For each script, this gives the entry point (or Main) subroutine for the file. ScriptExecIntervalX (X=1,2,3...) For each script, this specifies the execution interval in seconds. The default is 1 second.    Operation  The operation of the OPC Simulation Server is relatively straightforward.  Startup  At startup, the OPC tags are assigned the values in the Initial PV column of the database CSV file.  Simulation  The current version (1.1) of the OPC Simulation Server provides two forms of simulation: Scripting VB Script can be used to read and write values in the OPC server. This allows the user to customise the simulation to their requirements. Random Values The value of the tag is varied between the maximum and minimum values specified in the database CSV file. The demo version supports a maximum of 30 simulated tags, and the simulation features time out after 30 minutes. The OPC Simulation Server can be licensed for a nominal fee - see below. The OPC values can be set manually by simply typing in a new value. Individual items may be given a Bad status by ticking the Bad checkbox.  OPC Writes  The default is that the tags in the OPC server are read-only. To permit an OPC client to write to a tag in the OPC server, make an entry in the EnableWrite column of the database CSV file. Note that this requirement to enable writes only applies to the OPC interface - it is always possible to manually enter a value into the OPC server.    Scripting  Through the use of VB Script, the OPC Simulation server allows the user to simulate a process in a simple yet powerful manner. The script can reference the OPC Server tag database, through the following properties of the Sim object: TagVal(strTag) This gets or sets the value of a tag using the OPC tag name, for example: Sim.TagVal("23FC0020.PV") = 0.5 * Sim.TagVal("23FC0020.OP") + 10 AliasVal(strInstance, strAlias) This get/set property allows each OPC tag to be referenced using an instance and alias. The instance and alias names are specified in the OPC tag definition CSV file. This approach makes it easy to write generic subroutines for simulating process components such as a PID loop or a motor. For example, the following sample code could be used in a subroutine, where strLoop, the name of the instance, has been passed as an argument to the subroutine. rError = 0.01*(Sim.AliasVal(strLoop,"SP") - Sim.AliasVal(strLoop,"PV")) IAliasVal(strInstance, strAlias, nIndex) This is similar to AliasVal, but in addition it allows the OPC tags to be indexed. The index is specified in the OPC tag definition CSV file. For example, the following script updates an array of tags referenced as "NN". This fragment of code would typically form part of a subroutine, where strArray would be an argument to the subroutine. for i = 1 to 10 Sim.IAliasVal(strArray,"NN",i) = i*i next Here is an example of a simulation script in VB Script that uses the TagVal and AliasVal tag access routines: Option Explicit '-------------- Sub LoopSim() '-------------- ' Calling a subroutine, and using an Alias ' ---------------------------------------- Sim.TagVal("23FC0020.PV") = 0.6*Sim.TagVal("23FC0020.PV") + 0.4*(Sim.TagVal("23FC0020.OP")) + Sim.Rand call PID("Loop 1") End Sub '--------------- Sub PID(strLoop) '--------------- ' A very crude PID controller ' In fact it is really just using a bit of integral action dim rError rError = 0.01*(Sim.AliasVal(strLoop,"SP") - Sim.AliasVal(strLoop,"PV")) dim rOpCalc, K K = Sim.AliasVal(strLoop,"K") rOpCalc = Sim.AliasVal(strLoop,"OP") + Csng(K*rError) if rOpCalc > 100 then rOpCalc = 100 elseif rOpCalc < 0 then rOpCalc = 0 end if Sim.AliasVal(strLoop,"OP") = rOpCalc End Sub    Download  The OPC Simulation Server is available as a Microsoft Installer package: Download.    Purchase a License  A license for the OPC Simulation server can be purchased below using PayPal. Enter the name of the PC to be licensed on the PayPal site, or alternatively send it to the following email address: Email:   30 Tags $ 20   50 Tags $ 30   100 Tags $ 60   200 Tags $ 100   500 Tags $ 200   1000 Tags $ 300    Norwegian Customers Only  Includes 25% Norwegian MVA 30 Tags NOK 150   50 Tags NOK 225   100 Tags NOK 420   200 Tags NOK 750   500 Tags NOK 1500   1000 Tags NOK 2250