Hello PXI, Instrument control, and LabVIEW communities,
We are currently facing some issues with the local sense measurements. We are using PXIe-4140 4 channel SMU and PXIe-1088 chassis.
Our objective is to drive a photodiode with one channel (let's call it CH0) in the SMU while other channels (CH1, CH2, and CH3) are connected to other components. We apply negative bias voltage -1.55V between CH0_HI and CH0_LO and measured the current in this channel.
During our entire test, the other 3 channels are turned off using the method nidcpower.Session.disable() . However, when we measure the resistance with a multimeter among all local sense measurements outputs (for example, between CH0_HI and CH1_HI, between CH0_HI and CH3_HI, between CH0_LO and CH1_LO, between CH2_HI and CH2_LO, etc.), all of them show short-circuit. We doubled checked the control script and found that if there's no active session (all channels are turned off by nidcpower.Session.disable()), the connections between any two local sense measurement outputs are open. However, if there're one or multiple sessions being committed or initiated, local sense outputs are short.
Then, when the photodiode connected to CH0 is sensing light, the photocurrent we measured from SMU is too high, almost 10x higher than its spec.
We hope someone can help us with this issue. Unfortunately, we haven’t been able to find any documentation that addresses it. Thanks in advance for your invaluable time and support!
If there's any other information needed to address these issues, please let me know.
