iFix to AB Controllogix using OPC v7.30 Client Driver and String Data

[radfahrer]

Can anyone provide me the correct format for the I/O address needed to access a STRING in a Controllogix 5555 from iFix using the OPC driver via an RSLinx OPC server? I have RSLinx Professional rev 2.42, and iFix v3.0 using v7.30 of the OPC driver.

The default address format is Server;Group;ItemID;Access Path
The documentation for the OPC tool says to use ItemID|bytes for the address but I haven't been able to get that to work.

My tag in the Controllogix is Batch_ID and is a STRING with .DATA array of length 82.

Has anyone been able to read/write string data successfully with this combination of drivers?

Any help is greatly appreciated,

Greg Krueger

 

[russrmartin]

Not sure

I'm not sure about a string, but I'll forward the link to this post to someone here who might.

 

[Andybr]

Greg.

I am not sure about OPC but when reading strings via Linx to Fix32 using DDE you would attach the extension .SCxx to the end of the tag name (where xx is the number of bytes). I have never had a problem with this but I would add that I normally use a simple array of SINT's for my strings rather than the String data type. This is mainly because I started using CLX before the String type was available.

Andybr

 

[radfahrer]

Using the SCxx works

Andybr,

Your idea is correct...I got the exact syntax for the OPC driver from someone on the GE Fanuc website...below is an excerpt from that post for anyone else interested. In the example below Batch_ID is the name of the tag in the Controllogix PLC with a datatype of STRING (the Logix default string structure)

...

Note the ,SC82 is RSLinx specific, and it means use a C-style string with a length up to 82 bytes.

In iFix TX tag, use this I/O address:

ServerName;GroupName;[RSLinxTopicName]Batch_ID.DATA[0],SC82;No Access Path

...

Regards,

Greg Krueger