9.4.3 Switch Wiring
The thermal switch or cut-out is wired to the calibrator at the two terminals on the
back of the Micro-Bath labeled “DISPLAY HOLD”. The switch wires may be
connected to the terminals either way. Internally the black terminal connects to
ground. The red terminal connects to +5V through a 100 kW resistor. The
calibrator measures the voltage at the red terminal and interprets +5V as open
and 0V as closed.