I have a DAQ board connected to a multi-cal master board with PGA0309 boards on the interface board.
All cables seem correct
I have them set for 4 wire voltage mode, and I select the 4 wire voltage mode model in the software.
my supplies are on, the +9V to the DC jack, the USB is plugged in, the
15/-15V and 5V that supplies the DUT
the corresponding LED's light up,
I set up 4 temperature points. After scanning, the LED corresponding to Vdut is always bright, and it can complete the calibration of the initial temperature. However, after a certain temperature calibration, all calibration paths (8 ways) fail. At this time, the Vdut corresponding LED will go out. I measured the voltage between Vdut and GND and found that it was already no longer in 5V and turned into a 0V. By looking at USB DAQ Platform USER 'S Guide, I know that Vdut has been disconnected.
This happens so often that the calibration of the sensor can not be completed. However, as long as I shorten the time between the temperature points, the frequency of this situation can decrease.
By looking at USB DAQ Platform USER 'S Guide, I know that the software setting disconnects the Vdut.
I want to know why Vdut is interrupted in the calibration process so that it can't be calibrated.
I would like to know how to avoid Vdut being disconnected from the calibration process.