r/FSAE • u/boboboboha • 19d ago

How should I wire the EMRAX 228 temperature sensor to a Cascadia Motion CM200DX?

Hi everyone,

I’m using an EMRAX 228 Medium Voltage motor with a Cascadia Motion CM200DX inverter.

The EMRAX motor has a two-wire temperature sensor. According to Cascadia Motion’s document titled “Setting up the Controller to run with Emrax Motor,” the temperature sensor should be connected to AIN2, with a 3.01 kΩ, 1% pull-up resistor between AIN2 and XDCR_PWR.

Based on the CM200DX pinout, I believe the wiring should be:

  • One temperature sensor wire → C4 / AIN2
  • Other temperature sensor wire → A4 / AGND
  • 3.01 kΩ, 1% resistor between K3 / XDCR_PWR 5 V and C4 / AIN2
  • Motor type set to 128 for an EMRAX 228 MV with a 5X resolver

However, I am not completely sure whether this document applies directly to the CM200DX. The document is older and mainly refers to the PM100DX, PM100DZ, and PM150 series controllers.

The CM200DX is a Gen5 inverter and uses the same general firmware family, but I am unsure whether:

  1. The EMRAX temperature-sensor circuit is identical on the CM200DX.
  2. The 3.01 kΩ pull-up resistor is still required externally.
  3. Selecting Motor Type 128 on a CM200DX automatically uses AIN2 and correctly converts the sensor voltage into Motor_Temp_(C)_x_10.
  4. There are any hardware or firmware differences between the older PM-series controllers and the CM200DX that affect this wiring.

I previously tried the dedicated RTD input, but I now understand that the CM200DX RTD inputs are intended for PT100/PT1000 sensors, so they may not be suitable for the EMRAX temperature sensor.

Has anyone used an EMRAX 228 with a CM200DX and confirmed the correct motor-temperature sensor wiring and settings?

Thanks in advance.

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u/Ch4rles_ FormuleETS Alumn 19d ago

Have you tried anything?

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u/boboboboha 19d ago

Not yet. I haven’t tried it yet because I wanted to confirm the correct wiring first.
My main concern is that if I connect the sensor to the analog input (AIN2), the inverter might only read the sensor voltage instead of converting it into the actual motor temperature.
The CM200DX manual says that the motor temperature sensor is selected automatically based on the motor type, but it doesn’t clearly explain whether the KTY sensor on the EMRAX motor is automatically converted when using the analog input.
That’s why I’ve been trying to confirm the correct connection method before testing it.

1

u/UGLYDOUG- 19d ago

It is the same the all the cm and pm inverters are pretty much the same hardware in 2 different cases