It turns out that the Ring Heater itself can be used to measure it's temperature. The resistivity changes with temperature. We see the voltage change over the first hour when the heater is turned on: - this is due to an increase in temperature of the ring heater wire and a subsequent change in the resistivity of the nichrome winding.

I've estimated the temperature of the ring heaters over time using a nominal value of 0.00017 K^-1 for nichrome and the measured RH voltage from last week's test. You can see the results in the attached plot.

T0 = 1029555836 for Segment 1

T0 = 1029555847 for Segment 2

Voltage signals = H2:TCS-ETMY_RING_HTR_SEG1_V_MON_OUTPUT, H2:TCS-ETMY_RING_HTR_SEG2_V_MON_OUTPUT

Current signals = H2:TCS-ETMY_RING_HTR_SEG1_I_MON_OUTPUT, H2:TCS-ETMY_RING_HTR_SEG2_I_MON_OUTPUT