VAB

I ran into a situation - I have my Type K thermocouple input feeding directly into the PV value in my PID Config function block. The system was running fine and the output was firing at 80% for a particular set point. One of the thermocouples in my system failed in the middle of a cycle and the thermocouple read 32767 (out of range). At that point, the PID output locked to 100% and started heating up the system rapidly. This seems counter-intuitive of what actually should have happened as if the thermocouple value is much higher than the set point, you would think that the output % should go to zero. I did not make a note of the PID status at that time, but I believe from the definitions it should have been +8 (Integral Wind Down). Shouldn't the PID block catch the out-of-range thermocouple value and disable the output?