Connecting a PCI-6521 and a DMM PCI-4065

[MariMS]

Hi,

I would like to know if I can use the digital relay outputs from a PCI-6521 to switch between 4 lines in which I have to measure resistance using a DMM PCI-4065.

I´d like to know if there´s any issue if I connect four output terminals of the PCI-6521 together (to GND) and then I connect the other 4 sides of each output to each of the points where I have to measure the resistance. So when I measure the resistance for example of R1, I activate the output of the respective relay and I de-activate all the others 3 outputs. And then I could read the resistance with the PCI-4065. And so on... with the other 3 resistances. I´d like to know if there´s any issue connecting the outputs of the PCI-6521 with the input of the DMM PCI-4065.

Thanks!

[Rialter · Accepted solution]

Hi MariMS;

You can use the configuration you explain, although a 4 wire or 2 wire configurations are recommended depending on your application, for example if the resistance you are meassuring is greater than 100 kOhms you can use a 2 wire configuration, but if it is smaller you should use the 4 wire configuration. The following document has a more detailed explanation on them.

http://zone.ni.com/devzone/cda/tut/p/id/3610

I hope the information is useful.

Good Luck

Francisco Arellano

[MariMS]

Thanks for your answer Francisco.

I already did the configuration I mentioned with the DMM PCI-4065 and the PCI-6521 DAQ. It works OK, but I'd like to know how fast can I do the switching with this configuration. I'm trying to do it as fast as I can but then the DMM reading is not accurate 😞

Do you know if there is any software configuration I could do in LabVIEW to make the process faster?

Thanks,

Marisol

[Rialter]

Hi Marisol;

The main detail when you're working with DMM's is that yo have to choose between speed and precision, if you look at your DMM manual you will see that depending on the frecuency you want to measure, you get a different accuracy. I attach the link to the manual.

http://www.ni.com/pdf/manuals/374315f.pdf

I hope the information is useful.

Good Luck