Read-only rules for OPC server variables

I use ABB controller AC800M and OPC DA Server for AC 800M. Can I set some variables with read-only rules (from OPC clients)?

Some OPC server have this option, but in ABB I don't find options. I can hide variables for OPC clients in the controller (with attribute "hidden"), but I don't find option for read/write permissions.

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010110 Rank: 1296

Asked 6 years ago

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It is possible to set read-only permission for AC 800M OPC variables.

You need to configure "Property Permissions" tab in a program aspect.

See an example attached:

In this example value of MyVar_Readonly variable cannot be changed from OPC.

MyVar_Readonly value can be changed.

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by 010110 Rank: 1296 on 2/7/2013 10:07:13 PM | Like (0) | Report

I don't have 800xa. I have PLC AC800M, OPC server for AC 800M, and the scada is WinCC

by Linkinx64 Rank: 58 on 2/8/2013 2:34:26 AM | Like (0) | Report

Then you can change Read Permission property inside of .spr files in your project\application folder. But they are protected against changes with checksum. I know how to correct checksum value but not sure you can repeat this procedure (I'm using debugger).

by 010110 Rank: 1296 on 2/10/2013 11:51:49 PM | Like (0) | Report

Is there any documentation for this checksum?
Most variables are in Application (not in the programs) in controller project. I found variables in file ApplicationName.app. I see AccessLevel="Read Only" for all variables. Why the status is "Read Only" and I can read and write variables with OPC? May by I must set ReadPermission or WritePermission?

by Linkinx64 Rank: 58 on 2/11/2013 12:14:43 AM | Like (0) | Report

Yes, you must set "ReadPermission = Read"

by 010110 Rank: 1296 on 2/11/2013 5:22:10 AM | Like (0) | Report

Can you give me some hits for the debugger and the checksum.
I examined one virtual machine with 800xa and Control Builder M Pro. But the versions are very old (Process Portal A 2.1-2 Service Pack 2 and Control Builder M 3.2). I could not make an analogy between new and old version of Control Builder projects.

by 010110 Rank: 1296 on 2/12/2013 6:17:07 AM | Like (0) | Report

OK, I write one program with variable with ReadPermission="Read", but I can write in it! The variable is still RW.

Here is the code of MyProg.spr:

<?xml version="1.0" encoding="UTF-16"?><Program xmlns="CBSourceCodeSchema3_0" Name="MyProg" TaskConnection="SoftPLC.Normal" TypeGuid="85a89736-a11f-4e46-bcde-3b30add4c2f2" InstGuid="f88bfdd5-117a-4f37-8769-75303a98aeb2" SILLevel="NonSIL" SimulationMark="0" InternalChangeTime="2013-02-12-13:44:28.843" BuildVersion="5.1.48.40" SaveDate="2013-02-12-13:44:28.843" CodePage="1251" AccessLevel="Read Only" SafetyType="None"><Variables><Variable Name="localStatus" Type="dint" TypeGuid="d59be854-1395-4e4f-9cf6-6a4ba4ccdc98" AccessLevel="Read Only" SafetyType="None" Attribute="retain" InitialValue="" ReadPermission="Read" WritePermission="" AuthenticationLevel="None"/><Variable Name="Var1" Type="dint" TypeGuid="d59be854-1395-4e4f-9cf6-6a4ba4ccdc98" AccessLevel="Read Only" SafetyType="None" Attribute="retain" InitialValue="7" ReadPermission="" WritePermission="" AuthenticationLevel="None"/><Variable Name="Var2" Type="dint" TypeGuid="d59be854-1395-4e4f-9cf6-6a4ba4ccdc98" AccessLevel="Read Only" SafetyType="None" Attribute="retain" InitialValue="" ReadPermission="" WritePermission="" AuthenticationLevel="None"/></Variables><CommVariables/><FunctionBlocks/><InitValues/><CodeBlocks><STCodeBlock Name="CodeBlock1"><ST_Code>Var2 := Var1 +1;</ST_Code></STCodeBlock></CodeBlocks><Description/><CheckSum Value="11799"/></Program>

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Linkinx64 Rank: 58

Answered 6 years ago

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Read-only rules for OPC server variables

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