[SOLVED] Optical encoder wiring confusion

Thread Starter


Joined Feb 28, 2023
Hello everybody :)

I am trying to read the values from a direct drive linear motor's (SDLM-025-095-01-05) inbuilt encoder using a NUCLEO-F446RE board. It is a straight forward task, but I am slightly confused with the cables. ( datasheet )

Overall, the motor itself has 10 cables (as seen in the datasheet + transcription below). Since I just want to read the encoder values, and the negative channels, aka wires Blue & Yellow should not be touched (mentioned by the manufacturer), how should I connect the wires to my Nucleo board?

I understand I need 4 wires: Orange for Power, Green and White for the 2 Channels and finally the ground. But which wire is that? Is it Brown? I understand that the Black wire is the minus for the motor.

1. Orange - +5 VDC Power for optical encoder
2. Green - Channel A+ Output of optical encoder, TTL
3. Blue - Channel A- Output of optical encoder, TTL
4. White - Channel B+ Output of optical encoder, TTL
5. Yellow - Channel B- Output of optical encoder, TTL
6. Brown - Return for optical encoder and thermistor
7. Black - Motor minus
8. Red - Motor plus
9.Gray - Home indicator, TTL, Active high
10. Purple - Thermistor relative to Earth.


Joined Jan 8, 2017
I would think it is the brown wire. The motor will be electrically separate from the encoder part so the black wire will have no connection to the encoder.