Solution
This device uses an LM50 analog output temperature sensor connected internally to an analog input channel. According to the LM50C specification, the voltage-to-temperature scaling is:
//Vout = (10mV/degree Cel * temp(celcius)) + 500mV
return (vout - 0.5) * 100;
A temperature reading of -1140.9°C corresponds to approximately -10.909 volts, which means your device is receiving a full negative-scale value from the ADC. This likely indicates that part of the device may be damaged.
Here are some diagnostic steps you can try:
1. Check whether the temperature reading ever returns a reasonable value.
2. Verify if the normal analog input channels are functioning correctly.
3. In a VI or Test Panel, change the analog input channel to /_boardTempSensor_vs_aignd to read the raw voltage from the temperature sensor. See if this reveals any unusual behavior.