Hi Everyone,
I have a project at work and I am self testing the relays within our system. My system uses PXI-2532B matrices interfaced with TB-2641. The DMM is measuring from Matrix 3, and is measuring on row 0 (DMM +) and Row 1 (DMM -). This code I've built is known to work on our automated tester, however, on my new build for this ATE, I have found that two of my matrices (MTX1 and MTX2) are measuring 200 Ohms when using MTX3 to measure resistance on R0 and R1. The problem here is I am closing the switches in individual columns to short R0 and R1, yet I measuring a steady 200 ohms. It appears, it doesn't matter what columns I use to short my rows, I am still measuring 200 Ohms. I have tried measuring the shorted rows on a variety of different row combinations such as R2 and R3 and still results in 200ohms.
I have tried a couple other known good PXI-2532B modules to replace MTX1 and MTX2 and my system still results in 200 ohms. I have also tried shorting rows on my MTX3,but I will actually measure the expected shorted 1ohm results.
I have double checked my row cables, but don't see any issues with.
I have also isolated the TB2641 from MTX2 and kept MTX1 and MTX3 connected to its TB and manually measured with an external DMM the resistance at my row ribbon cable coming out of MTX1s Terminal board, and resulted in 200 ohms. I am lost to what exactly could be causing me to measure an open connection when in shorting my rows internally. Could my terminal board really be causing this somehow? the rows doesn't measured 200 ohms until switches are closing connections.
Any thoughts, comments would be greatly appreciated.
Thanks,
Charlie
