Hi,
I have customers using the following problems:
The customer's equipment has detected the temperature less than zero, and only the three channels of the external three-tube temperature measurement are less than zero at the same time, the other channels are normal, the probability is very low, there have been two or three times, when the read temperature value is -256℃, after restarting the recovery.
According to spec, -256℃ corresponds to short circuit, but our situation is not necessary.
In addition, the customer short-circuit and open-circuit treatment of the three-tube PN junction, the temperature read out is -256℃.
The following is the circuit designed by the customer, please help to find out the reason for this situation, thank you!