OPC Data Specification from MicroSCADA using Property Transfer

I am currently on site in Kazakhstan and am trying to get some signals from a MicroSCADA into my 800xA system (PM861, 5.1 FP4 RU2). The signals are being supplied over OPC and I am bringing them into my controller using Property Transfer.

The signals are available on the Control Structure under the generic 800xA OPC Server but when I try to connect using the Property Transfer aspect whatever I put in gets rejected as INVALID. I have installed a Matrikon client on my machine, this reads the signals without any problems.

The signal format as reported in the Control Structure is something like

$'[Control Structure]Root/MicroSCADA:\P\SiteDOCPMU_ME1\16' where MicroSCADA is the name of the OPC Server in the Control Structure and \P\SiteDOCPMU_ME1\16 is the name of the signal.

Anybody have any ideas? I have got this working with a different syntax on my development Virtual Machine but if I set up an alias with a similar format to this one nothing works.

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RobertHarrison Rank: 411

Asked 2 years ago

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I assume the colon (:) and backslashes (\) disturbs the expression parsing.

Try preceeding each with an extra backslash.

$'[Control Structure]Root/MicroSCADA\:\\P\\SiteDOCPMU_ME1\\16'

It is also recommended to specify the aspect name to read from;

PATHTOOBJECT:ASPECT:PROPERTY

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by Stefan Stromqvist AKS expert

Rank: 1 on 12/26/2015 7:34:54 AM | Like (1) | Report

If object is "[Control Structure]Root/MicroSCADA"
and property name is "\P\SiteDOCPMU_ME1\16"
try:
$'[Control Structure]Root/MicroSCADA:Control Connection:\\P\\SiteDOCPMU_ME1\\16'

But if object is "[Control Structure]Root/MicroSCADA/P/SiteDOCPMU_ME1" and property name is "16" try:
$'[Control Structure]Root/MicroSCADA/P/SiteDOCPMU_ME1:Control Connection:16'

Expected syntax is:
OBJECT:ASPECT:PROPERTY

If any of these three strings contain special characters such as backslashes or colons we're in trouble and need to "escape" each of them with and additional backslash from being interpreted as limiters.

by RobertHarrison Rank: 411 on 12/26/2015 6:12:37 PM | Like (0) | Report

That's great, thanks. The colons aren't a problem, I've had it working with unescaped colons in my development environment but I think you're right and the unescaped backslashes are what is causing the problem. Looking at the Control Connection field the property is 16 but the Matrikon explorer shows a subproperty of AI (totally unreported in Control Connection) which I might try.

An ability to browse the address space would be really useful here!

by Stefan Stromqvist AKS expert

Rank: 1 on 12/26/2015 11:57:30 PM | Like (1) | Report

OK. The uploaded itemIDs can be somewhat examined at the Advanced tab of the Generic OPC Uploader. Perform a "retrieve" and examine the .ocs file that is the result from that. You can even edit that file before going ahead with "append". Changes will go lost at next retrieve or regular upload though.

by RobertHarrison Rank: 411 on 12/27/2015 1:56:42 AM | Like (0) | Report

Now we're getting somewhere. I tried putting the Aspect ID string in using this format $'{94709EB2.......}:16' and this validates and reads. So whatever needs to be put in the final part needs to be separated by a colon.

I'm a bit nervous about leaving it like this, firstly because it makes maintaining the system after I go home difficult but also I can never remember whether the Aspect ID string will change if the customer does an upload or makes other changes.

by Stefan Stromqvist AKS expert

Rank: 1 on 12/27/2015 9:17:30 AM | Like (0) | Report

IDs have the benefit of being free from special characters.

I'm on leave until Jan 4th and will not be able to experiment/check/verify things until then.

Should not be that hard to test if upload changes stuff or not.

Remember to check [Workplace Structure]Web System Workplace:Operator Message list for overruns or failed writes. Property Transfer expect "unlimited" write performance in the recipient OPC server, few servers are able to fulfill that.

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Stefan Stromqvist AKS expert

Rank: 1

Answered 2 years ago

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OPC Data Specification from MicroSCADA using Property Transfer

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