Measuring both voltages and resistances with DMM + Switch every second

[Chickentree]

Hello,

I have a PXI-4071 DMM and a PXI-2527 Switch. I need to measure 24 differential voltages and 2 thermistor resistances every second. I'm trying to do switch scanning with the DMM. The switch will be in 2-Wire 32x1 Mux mode.

My question is, is it feasible to change the DMM measurement type between DC Volts and 2-wire Resistance and acquire 26 measurements every second? Is it going to affect the DMM's lifespan in any way?

Any relevant tips will be appreciated.

Regards,

Pomirobotics

[crossrulz · Accepted solution]

Changing measurement modes is kind of an involved process for the DMM and is slow.  I would use a 5V supply and a resistor to make a voltage divider with the Thermistors and then you can calculate the resistance.

Also, is there a reason you are not just using a PXI DAQ?  It would be a lot simpler if all of the voltage levels are within 10V of ground.

[Chickentree]

Thanks for the answer. It seems I will have to go with the voltage divider option after all.

I already have a PXI-6225 DAQ (which can provide 5V for the voltage divider). While each of the 24 differential voltages is less than 5V, some individual voltages can go over 100V referenced to ground. It seems there is no way to use the DAQ for this application.

Regards,

Pomirobotics