The thermocouple has two pins (a ground, a 0 to -0.0004 when activate the bobbin to run the gas.) I want know how can I detect whether the gas is open or not without adding a sensor to the system. Can I do it by amplifying the voltage or something like that?
Asked
Active
Viewed 87 times
0
-
2I would try to use whatever signal is used to "activate the bobbin" whatever that means, instead of using the thermocouple itself. Thermocouple amplifiers are non-trivial (not terribly *hard*, but not terribly easy either). – Hearth Jul 09 '22 at 13:50
-
1Is this part of an existing device? Is the "gas" you mention something combustible like propane or natural gas? If so then presumably that thermocouple is already connected to something else which is already reading it, and that something is probably part of the safety system for this device, and you probably don't want to be messing around with that. – brhans Jul 09 '22 at 15:07
-
1That voltage sounds very low for a typical thermopile-operated safety gas valve. I would expect closer to half a volt or a volt. You would have to be very careful adding on anything to that in order to ensure there is zero chance of a fault in anything you connect causing the gas valve to energize & open, thus releasing gas without a flame. Inevitably the gas/air mix would then find an ignition source. Maybe you should detect the flame by some other means, though the crummy ESP32 on-chip 1V FS ADC with lots of series resistance on both ground & input *might* be okay, I would counsel caution. – Spehro Pefhany Jul 09 '22 at 16:15
-
Do you want to detect a falling temperature when the gas flow is enabled? – Jens Jul 09 '22 at 16:39