Parameter bindings in OpcItemPath for a UDT that references a LOGIX UDT array

General Discussion
1

I have a Control Logix PLC and am using the standard Logix Ignition driver to access tags.

I want to create a single Ignition UDT in which I can use the name of the UDT instance to create the OPCitempath (no parameters).

For example:
Assume the name of the array UDT in the PLC is 'productData[2]'.
I want to name my tags productData_00, productData_01 and be able to have the UDT parse the array element number from the name and pass into the OPCitempath parameterization properly.

Reason: To make new tags I simply duplicate and make sure the array index number in the name is correct. No messsing around with the OPCitempath directly or entering array index numbers in a parameter which is very easy to overlook and forget to change.

I currently can do this with non-arrayed UDT's with the following entry in the
parameter:

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But with an array UDT I can't use the root instance name because it has the array index in it in the wrong format for the OPCitempath .

The correct path syntax for the the Control logix is:
ns=1;s=[MYPLC]productData[0].count

The code above creates this incorrect path:
ns=1;s=[MYPLC]productData_00.count

So the only way I can figure out how to do this is to add a parameter called 'arrayIndex00, arrayindex01' and nest the UDT array elements inside another UDT. Very messy. And I have varying lengths of UDT arrays all over in the PLC.

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Ideas ?

Assume the following PLC UDT array for my example:
productData[2]

The productData UDT is defined in the PLC as:
productData[0].name (string)
productData[0].count (integer)

when the tag productData is imported into Ignition it creates a folder called "productData"

The tag paths are:
productData/productData_0_/name
productData/productData_0_/count
productData/productData_1_/name
productData/productData_1_/count

2

There's no way to parse the array index out of the instance name like you want. Consider using my driver's JSON udt and tag tools during development--you'll get most everything preset for you. It's easier to delete the stuff you don't need than to create the stuff you do need.

(And, as long as you don't use the "compact" versions, the resulting types and tags work with IA's native driver, too.)

3

Thanks for quick response and it is too bad the parse feature doesn't exist (extract numeric value from the string would be great).
One thing I am using the ignition UDT for is to enter the units of each tag. If I do a straight tag import all the unit fields are left empty. Especially important because sometimes I write systems where users can select their units for display on the HMI. I use the tag's units as the basis for knowing how to convert. If the JSON tools you mention just do imports that create individual tags I still have the problem of maintaining lots and lots of tags once the import is complete.

4

Import from what? If you populate JSON with engineering units, they'll import. The real problem is that Rockwell doesn't expose tag units to third party drivers. But if you can get them in a CSV, you can script an import that does everything "right".

Anyways, I recommend playing with my driver's development aids.