I am experiencing troubles trying to subscribe an array into the ignition opc ua server.
Versions I am running:
Ignition v7.9.2 (b2017041315)
Logix driver: 3.9.2 (b2017041315)
PLC: Compactlogix 1769-L36ERM Revision 30.011
In the PLC there is a program scoped variable:
L_Product_Par.Act.Parameter.Nr which has datatype REAL[2500].
Using our own OPC ua client we are able to subscribe to the individual elements like this:
L_Product_Par.Act.Parameter.Nr[5]
But due to the size of the array I would really like to address the array as a whole like this:
L_Product_Par.Act.Parameter.Nr
Is this at all possible with my current setup?
Regards,
Rudy
Ignition’s OPC UA server and drivers do not currently use array types. Instead, it exposes them as folders containing the individual elements.
Thank you Kevin for your response,
how would you suggest to address the datapoints?
I have tried putting all reals in one row and writing it into a massive STRING of 10000 characters but apparently only the default STRING datatype with a character length of 82 characters is supported by the Ignition OPC ua server.
thanks in advance for your response,
regards,
Rudy
It does support reading custom String UDTs of any length but I think writing to those UDTs is limited to ones whose length lets it fit into a single CIP request.
If your UA client subscribes to all the elements of the array our Logix driver will read the array as a whole behind the scenes - it just doesn’t expose an array value in the OPC UA server.
Instead of using a subscription I am using ReadValues of a collection of NodeID’s. The collection contains all 2500 members of the array. This gets me the values of all id’s within one message.
This is not a subscription but it still works for me.