Wiring... Center 306 probes to Phidget

#1: Post by **bharmon91** » December 28th, 2022, 7:31 pm

In essence, I am just seeking wisdom on how to go about unwiring my center 306 probes from my Kaldi fortis and wiring them to my new phidget that comes in tomorrow. The end of the probes on the 306 have a yellow casing around the wires...this may sound dumb...but I'd rather seek wisdom than ruin something.

#2: Post by **Trjelenc** » December 29th, 2022, 6:43 am

They probably look like this right? K-type thermocouples?

All you do is unscrew those tiny screws on the yellow plug and take the wires out. You then insert the wire ends into the Phidget terminals and screw those to clamp them in. Might take some fiddling around to make sure you got them the right way, you'll instantly know by looking at the temp reading they give

#3: Post by **randytsuch** » December 29th, 2022, 10:01 am

If you heat up the thermocouple, and the temp goes down, the 2 wires are reversed, and you need to switch them at the terminals.
I usually just pinch the end between my fingers, the body heat is enough to change its temperature.

For the type K's I just connected, the red wire goes to the negative terminal.

#4: Post by **jfife** » December 30th, 2022, 7:06 pm

Take a look at this thermocouple wiring color-code table:
https://www.tc-inc.com/thermocouple-wir ... olors.html

I had a go-round with some Canadian probes with a white sheathing with a blue stripe which were made overseas. Red can be (+) , or it an be (-). It depends on what country your thermocouples were made in, and what colors are on BOTH wires and sheathing.

Anyway, testing to see if body heat makes the temperature reading go up is an excellent way to get it right. You can't beat an empirical
test. Just be sure you are using type-K with most phidgets.