Read data from secondary thermistor on TC4820

[dc2917]

TC4820 features an optional secondary thermistor input for sensing alarm conditions. Interest has been expressed in making use of this feature.

Appendix B of the manual hopefully contains the information required to do this. A quick scan of section "IV. Serial Commands" makes me think we might just be able use request_decimal("040000") (cf. request_decimal("010000") for reading the control thermistor temperature), if all we want to do is read the temperature from this secondary thermistor.

• The retrieved value should be written to the log file, along with that of the control thermistor.
• The retrieved value could be shown on the GUI, but where to put this is not obvious, as it won't be related to the hot or cold blackbodies.