4 wire resistance measurement of DMM PCI 4065

[KB29]

I need to measure the contact resistance using 4 wire measurement in DMM PCI 4065. Based on the given order of the PCI slots(as in the manual) i.e. Hi_V, DMM Lo, Hi_Amp, Lo_sense, I am unable to do the 4 wire measurement. The voltage is positive (between Hi_V and DMM Lo) and the current reading is negative (between DMM Lo and Hi_Amp). I can get the 2 wire measurement.

But when I change the order of the connections as Hi_V, Hi_Amp, DMM Lo, Lo_sense, I can get both 2 and 4 wire resistance. My current is now positive and the voltage is negative.

I find this really strange as it is not behaving as per the user manual.

Can u provide some suggestions on how to correct this or is there any issue with the product?

Thanks

Kaushik

[Steve_B]

Hi Kaushik,

Thank you for posting your question, you can make a 4 Wire Resistance measurement with the PCI-4065. The connections to the DUT can be made according to the following link. You can hover your mouse over each type of measurement and the image will update with the connections.

NI PXI/PCI/PCIe-4065 Front Panel Connections

You will see that the 2 Wire Resistance measurement has a DUT connection between HI and LO on the DMM and that the 4 Wire Resistance measurement has the same DUT connections but also connects the HI Sense to HI and LO Sense to LO. For the best measurements you will want to connect the Sense Connections to be made as close to the DUT as possible. For the benefit of the community, some additional 4 Wire Resistance measurement information can be found at 4 Wire Resistance Measurements.

There is a caveat to be aware of when using the NI 4065 to make 2 and 4 Wire Resistance measurements that does not apply to an NI 407x DMMs. With the NI 4065 the Sense connections need to be removed from the DUT to make a 2 Wire measurement. When making a 2 Wire Resistance measurement the HI Sense and LO Sense terminals should be open.

Can I Measure Resistance in 2-Wire Mode When DMM is Connected to DUT in 4-Wire? 

This information should help you make the connections for your 2 and 4 Wire Resistance Measurements with the PCI-4065. Post back if you have additional questions.