So I have a Mesa 7i96 that I'm using to convert a machine to LinuxCNC. I'm working on setting up the limit switches, which are NPN NO inductive sensors, and have come across an odd problem. Whenever one switch activates, it drops the voltage on all the other inputs enough to trigger all the signals at once. The sensor wiring is as follows: Brown - +24V, Black - to input, Blue - GND, with the 7i96 input common pin wired to +24V. For example, when one sensor is triggered and connected to the board, it reads a few mV, and the others read 16.3V. When it is disconnected from the board, it reads ~24V when resting and ~0V when triggered as expected. Is this expected behavior from this kind of configuration? I thought the inputs were isolated? The common pin voltage does not drop which seems to suggest it's not overloading the power supply. Any suggestions on ways to make it work?
Is this normal behavior for sinking inputs?
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