I just purchased a T3-BB-W-1kpt. I could find nothing in the manual or in a forum search that discussed how to connect a 3 wire 1kpt sensor and how to configure it with T3000 software. All I found was things for an product that seems to be no longer sold that was just for 1kpt sensors.
Can someone please point me to the appropriate settings and wiring docs?
thanks,
jerry
We commonly use the two-wire 1K PT sensor.
The one you are using should be a three-wire 1K PT sensor, which typically has one signal wire and two compensation wires.
You can connect one signal wire and one compensation wire to the two terminals of the AI port on the T3-BB-W-1KPT.
This will treat it as a regular two-wire 1K PT sensor, but it will not be able to perform the three-wire compensation to eliminate lead wire resistance.
This is disappointing.
Next question: When I measure the wire resistance of the loop pair, how do I put that is as a calibration for the input? Let’s say the loop measures 3.55 ohms, what do I put in?
If the wire resistance is 3.55 ohms, it can be converted to a temperature of 0.92°C. In the T3000 software’s INPUT interface, you can perform calibration by entering 0.9 in the calibration field and selecting the “-” symbol.
Thanks, that’s what I needed.
for people following this, the platinum RTDs have a temperature constant of .00385 ohms per degree C, so a 1k pt rtd will be 3.85 ohms/C. That’s how Lijun came up with the .92 C calibration. It’s negative because the loop resistance increases the overall reading.