I am using an IR sensor based on a K type sensor.
And I notice one issue with the TC pin.
If the HB, E0 and E1 is defined as high. shown as below
digitalWrite(HEATER_2_PIN , HIGH);//main bed
digitalWrite(HEATER_3_PIN , HIGH);//feed bed
digitalWrite(HEATER_1_PIN , HIGH);//temperary

the reading of TC2 increases briefly 450
for eg: 100 (with HB, E1, E2 high) would turn to 450

If only E1 is defined as high, and HB, E0 is defined as low shown as below
digitalWrite(HEATER_1_PIN , HIGH);//temperary

the reading of TC2 is staying at 100.

the reading of the TC2 is done in under the same temperature.
So I don't really why.
PS, the IR sensor is powdered by E1, HB and E0 powers two heating sheet.
Thank you.