Getting HSDIO attributes using the niHSDIO Property Node VI

[jeroendc]

Hello,

I have a PXI 1085 chassis with a few PXIe-6555 HSDIO modules installed. I'd like to read certain NI-HSDIO attributes, for which purpose I am using the 'niHSDIO Property Node VI'.

When reading attributes that are not channel-based, I observed the following:

1- reading the output terminal of a module's exported start trigger works just fine

2- when reading the output terminal of a module's exported script trigger without specifying a channel, I get this error -1074118650: 'You must specify exactly one channel or repeated capability from which to retrieve an attribute.'

3- when reading the output terminal of a module's exported script trigger with specifying an empty string as 'active channel', I get the same error.

4- when reading the output terminal of a module's exported script trigger with specifying a channel string (e.g. '0') as 'active channel', I get the following error: -1074135008: 'Unknown channel or repeated capability name.'

The above test cases are illustrated in the attached vi: ni_hsdio_attribute_question_jdc.vi

Could anyone who has similar hardware reproduce this behaviour, or tell me what I'm doing wrong when I read the Exported Script Trigger Output Terminal? Any insights would be greatly appreciated...

Thanks,

Jeroen

PS. As I am new to this forum, please do let me know if you feel this question should be asked in a different forum, or if some vital information is missing in this post.

[TobiasG]

Jeroen,

Before you can use a property node that takes an Active Channel, you must assign active channel(s) to that session using Assign Dynamic Channels or Assign Static Channels. Once you have assigned channels to that session, you should be able to use Active Channel properties (but only for those channels you selected).

For example, if you call Assign Dynamic Channels with channels 0-7, and then try to read a property back on channel 8 in that session, it will throw an error.

The HSDIO examples all use this paradigm; hopefully that plus this explanation will give you enough guidance.

For future reference, questions on NI-HSDIO devices are typically asked in the Digital I/O forum.

Hopefully that helps. Please let us know if you have further questions.

[jeroendc]

Thanks for your help, Tobias.

May I elaborate a bit further? As you said, I can only use a 'property node that takes an Active Channel' if one or more channels have been assigned to the session.

1- could you explain why the NIHSDIO_ATTR_EXPORTED_SCRIPT_TRIGGER_OUTPUT_TERMINAL property takes an active channel? I would not expect this attribute to be channel-based.

2- I've modified my example: I'm now assigning dynamic channels and committing the session before calling the property node. Still, I get exactly the same error messages.

Many thanks for your assistance!

Jeroen