i am putting together a temp controller for my Lee 4-20, and i am using the Mypin TA4 PID... got most of the setup for the PID figured out except the temperature offset... what this feature does is correct the temp if your TC is a slightly off either high or low... my TC reads a few degrees low, so i need to set the "Input Offset Parameter" to a -2.5 degrees, but i can't figure out how to set a negative temp in the unit... anyone know how to make the offeset temp a negative number?