I have three SNAP-PAC-AITM8 cards in my system along with various other cards (analog, digital, etc.). The system is running a combustion system for testing. Lately, something is malfunctioning in the system and some or all of the t/c’s will change from type K to +/- 75 mv. Usually the other problem that corresponds with this is the three blowers that are controlled via VFD’s with a serial card will also start operating erratically. The speed will change say from 40% output to 0% and back to 40% output randomly even with the operation in manual mode instead of in PID mode). When the problem is detected, I shutdown the system and I have to use PAC Manager to change the t/c’s back to type k’s. This will happen randomly. Sometimes multiple times a day or sometimes it won’t happen for over 2 weeks.