How to retrieve the scaling information from cRIO channels, running in Scan Mode.

[LDBM]

From the Windows side, this can be done by reading the project file and looking up some ProjectItem properties  at the Variable level. But how to obtain the scaling information of a given variable, programmatically, from the cRIO target? Thx.

[jkurtw · Accepted solution]

Take a look at the variables.xml file on the cRIO controller at ftp://<IP address>/ni-rt/config/variables.xml

It is not the cleanest way to get it, but it has the information you are looking for. 

Kurt 

[Ben_S]

BSI,

What modules are you using? 

This KnowledgeBase Article shows how to access information about a module programatically, it may be different than you're module, but you can do the same process to access information about the module you're using. Basically, from the reference of the module you're using, you can use a property node or invoke node to access information about the module itself. I'm not sure if scaling is visible or not for the module you're using.

[LDBM]

Thanks Kurt and Ben for your feedback.

I think Kurt's solution will do for now. I have several modules, and I am looking for the Min, Max, and scaling info and it it accessible via the xml Kurt described. One has to make sure the modules are deployed, so that the proper information is in the file. I have several Analog Modules (in and out), and I first tried with the property node as described but the properties I am looking for are not there.

Modules:  9208 (4-20mA AI), 9213 (Thermocouple), 9403 (DIO, no need of scaling), 9264 (AO), 9206 (0-10V AI). Specifically, I was looking at the scaling info for the 9206, and it was not there. I could only find some range info for the 9206, none for 9208, some for 9213, and no reference for 9264 (see diagram).

Laurent.

[viScience]

What about a variables.xml parser built into MAX?  Wouldn't that be nice?  Even nicer would

be the ability to change cRIO IO scaling from MAX.

[Dave-C]

Hi sachsm,

I would recommend submitting these suggestions to the NI Idea Exchange to see if the idea is popular and can gain the attention of NI R&D.  Unfortunately, with the way our drivers are set up, it would require a change to those to be able to implement what it sounds like you're proposing.

Regards,

-Dave C