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Python bindings for NI Modular Instrument drivers.
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Cannot connect to a PXIe-4139 card located at some IP address #2063

Open heydaridlm opened 1 month ago

heydaridlm commented 1 month ago

Description of issue

I have a PXIe-1075 chassis with some PXIe-4139 cards. I have connected the PXIe-1075 to my PC using a crossover ethernet cable and established an intranet between that PC and the embedded PC on the 1075.
I tried to use VISA to communicate with the PXIe card (located at, e.g. visa://xxx.xxx.x.x/PXIyy::0::INSTR). 'x' and 'y' are numbers.

 import nidcpower
 addr = 'visa://xxx.xxx.x.x/PXIyy::0::INSTR'
 session =  nidcpower.Session(resource_name=addr)

This results in the following error

 InvalidRepeatedCapabilityError: An invalid character (Multiple '-' or ':') was found in repeated capability string

Perhaps nidcpower does not support connecting to remote PXI cards?

Steps

  1. Establish an intranet between external computer and PXI chassis
  2. Verify PXI resource is accessible by external computer through pyvisa (even though PXI instrument does not support VISA commands)
  3. Attempt to open that same resource with nidcpower: FAIL
tobiasgordon commented 1 month ago

You are correct, NI-DCPower (and other drivers supported by nimi-python) do not support remote access via VISA.

That said, you have options!

NI gRPC is one option. See https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000oxQGCAY&l=en-US for more details.

Others include using other remote calls. We have had success using rpyc as well, which is quite lightweight.