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Former Member

RSLinx OPC-DA / UDS - Some tag values can not be seen.

We have a problem to see values of some tags from RSLinx using UDS.

We are connected with UDS Version 4.0.322.

I realize that the tags of type "Long" can see the values just fine, but other data types of tags (short, float, double and boolean) we fail to see the current values and returns the following error:

"Problem with tag:" [CAL ] CLP1_1: 10: I ", due to: [RSLinx OPC Server]: The item is no longer available" or shows no value for the tag.

Can I have some help?

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1 Answer

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    Former Member
    Dec 10, 2010 at 06:24 PM

    I've seen this issue with RSLinx (only longint values get trasferred). Mainly the issue is with the RSLinx product, not being certified with OPC-DA standard greater than 2.05a (which is one of the requirements of the UDS 4.x product).

    Try add more tags in the PLC using local conversion to LONGINT (i.e real or floating point values come as longint, multiplied with 10/100/1000 depending what accuracy you need). You convert them back to their real/floating point value with MII, after you push them through the OPC chain.

    Option 2 is to forget about RSLinx and use a product compliant with OPC-DA standard > 2.05a (i.e. Kepware).



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    • Former Member

      Hi Paul,

      Thanks for your response.

      I'm trying to use Kepware, but I can not configure the device ID, I tried to assign the IP on this property but the return is not a valid device id.

      Any suggestions?