07-25-2014 03:55 AM - edited 07-25-2014 03:56 AM
Yesterday when I was doing maintenance on an actuater I noticed the valve wasn't closing fully when connected to a NI 9625 AO 0-20mA signal. The valve operating range is 4-20mA. The NI9625 was fixed at 4mA by distribution system manager.
I measured this signal with a mA calibrator and I measured 5,325mA.
I fixed the signal to 20mA and than I measured 19,412 mA.
I did the measurements again directly at the module, cables of this output disconnected, with the same results.
Other outputs are currently beiing used. But they seem to be working (no strange behaviour of valves).
What could be the problem? Is the channel broken?
07-25-2014 06:36 AM
It is likely just a simple calibration issue. When was that module last calibrated?
07-25-2014 07:00 AM
Thank you for your reply.
As far as I know our modules have never been calibrated.
It seems strange to me that it is a calibration issue, because it is a realy big offset.
Can I calibrate the module myself?
07-29-2014 11:48 AM
Well I can't find the 9625 but I found the 9265 calibration procedure 😉
http://www.ni.com/pdf/manuals/372667b.pdf
Time to establish a calibration/maintance procedure for your device 😉
07-30-2014 01:57 AM
Hi,
Indeed I mentioned the wrong number. It is the 9265 module.
Thank you for the document. Luckily we also have cDAQ 9178. I will perform calibration when system is off.
Best regards,