Thermocouple Amplifier Testing

[b]NOTE[/b] Thermocouple support is optional

After surface mount soldering the thermocouple amplifier and passive support components to the HeaterMeter PCB it is helpful to perform testing before completing the entire build.

Before applying any power, check for shorts and good connections on the amplifier IC. 1 to 1, 2s to 2s, 4s are not connected to 5, and so on. N is not connected to anything.

Apply any voltage source (3V-36V), such as a 9V battery, to the through-holes shown above. Connect positive to 5 and ground to 2 and measure the voltage output at 4, or the big hole connected to 4. The output voltage should be a within 0.1V of the input voltage. Note: Do not apply more than 3.3V after completing assembly of the entire HeaterMeter, only the thermocouple assembly is tolerant of this voltage range!

Now short the two thermocouple input pins together with a piece of wire. The output should drop to room temperature (in Celsius) * 5mV or about 0.10V-0.15V. If the AD8495 is still warm from soldering, it will affect this reading slightly. Ignore the fact that this image says "Thermopcouple", I'm not re-making it.

If both these readings check out, your thermocouple amplifier is fully operational and you may continue HeaterMeter v4.2 Assembly.