I have a PT 104 for voltage measurement. The voltage reading failed from early this week, the data shown by pico recorder is not the voltage across the Pin 2 and pin 3, which I measured using a multimeter.
I connected wires V- and V+ to the to pin 2 and 3 separately, and left Pin 1 and 4 unconnected. The vltage was from -0.3 to -2.2 V, and I scaled it to 0.3 0 2.2 V. At the beginning it gave smaller numbers than what I expected (i.e, when it should be 0.57, the reading was about 0.3), but still reasonable trend curves when the voltage changed. But from this week it seems not working at all. The voltage always slowly dropped from 2.8 V to 0 V after a connection, no matter what the real voltage is.
I wonder where the problem is. I checked the PT 104 by a PT 100 and the 4 channels all worked well.
Thanks a lot!