Temperature Sensor Resistor Wiring

What would be the proper way to wire a pull-up resistor for an analog temperature sensor? Seems like soldering it between two wires would not be a good idea.

A pull up resistor needs to have one end connected to the reference voltage (typically 5V). This connection could be via a crimped or soldered connection. The other end if the resistor needs to be spliced (again crimp or soldered) into one of the wires going to the thermoresistive temperature sensor. This same wire needs to be the signal wire connected to the ECU or data logger. The other wire to the temperature sensor needs to be connected to the ECU or data logger signal ground (0V).

For best results get a precision (1%) resistor of the required value. Typical 5% resistors can reduce the accuracy of your measurements (but you may be able to calibrate that out).

Thanks

While this is an old post…

following up: if the ECU has only 1 5V supply and 0V, does the resistor impact any other installed sensors not needing say a 4.7kohm resistor? If so, does placement matter?

Say wiring up a trans temp sensor to an AVI, requires a 4.7kohm resistor… you’d wire the resistor between the 5V supply and signal wire at the sensor? Sensor 0V runs back to ECU unspliced.

That is correct -- the voltage divider is only happening on the AV Input you are using. So you would splice the 5V supply pin to all the sensors, some may have a pullup, some may connect directly to the Voltage Input connection for the sensor.

BTW - your M150 has 6 temperature inputs that have a built-in pullup resistor, so the wiring is simple. The one caution is that each AT channels has a specific 0V (0vA, 0VB, 0VC) that must be used. Look at the help for any sensor "reference voltage" parameter.

Right. However the build I am doing has a 6R80 package which in the wiring states I have to use a 4.7kohm resistor between Sensor 5V-A and the trans temp sensor. So wanted to wire that resistor in by the actual sensor.

See attached

I would have to study the package see if there were different options. That picture does just say "sample pinout", so you might have other options (ie, you can change the resources in the package with M1 Tune). But you should understand the whole system and why those choices were made.

https://www.milspecwiring.com/MoTeC-USA-6R80-Swap-Firmware_p_2834.html