Determining 4070 Self Calibration P/F

[S-T-G]

I'm programatically self-calibrating 13 PXI-4070 DMMs on a daily basis and need to determine whether or not the self-cal passed on each. I've never had a self-cal fail so I don't really know what to expect. Will an error or warning be produced? If so, what are the possible error/warning code(s) I need to check for? Currently I'm comparing the self-cal date obtained from the DMM prior to running the self-cal with the date obtained post self-cal. I'm assuming the date doesn't change if the self-cal fails. Is this a good assumption?

Thanks.

[TobiasG · Accepted solution]

S-T-G,

Depending on what environment you are programming in (LabVIEW, C, CVI, etc.) it will vary slightly as to specifically how you can check whether or not any function passes.  A successful return from a function returns 0, so you can check for that.  If you receive a non-zero number (which you should if the call to self-cal fails for any reason), you can determine what that error code means. In LabVIEW, for DMM you can use the niDMM IVI Error Converter VI to interpret the error.  If you are using CVI, C, or another text-based programming language, you can pass a non-zero return value to the niDMM_GetError() function.

As for what specific error codes that can be returned from a self-calibration failure, there are a few but it is difficult to give you an exhaustive list, as it can fail for a number of reasons (overrange, driver not installed correctly, etc.).  The proper way to check for failure is to check against IVI_SUCCESS or zero, then if it fails to call the appropriate function to get the descriptive error string.  If you are curious, nidmm.h shipped with the driver contains a list of most NI-DMM-specific error codes.

For a better idea as to how to do this, I would suggest taking a look at the Self-Calibration examples that ship with the driver.

I hope this helps.  Let us know if you have any further questions.

Thank you,

Tobias Gordon

Software Engineer

Digital Multimeters
National Instruments