NPN Open Collector Output Incremental Photoelectric Rotary Encoder (AB 2-Phase) – Connection To PLC High-Speed Digital Discrete Inputs
A short write up describing how to connect a NPN Open Collector Output Incremental Photoelectric Rotary Encoder (AB 2-Phase) to a PLC’s High-Speed Digital Discrete Inputs.
It generates AB two-phase orthogonal pulse signal though the rotation of the grating disk & optocoupler.
Encoders are used for: speed, angle, angular velocity & other data measurements.
If one looks at generic incremental encoders, such as the CN3806-AB-600N or HN3806-AB -400N, the following applies, in general:
The wiring color-codes (it may be different from encoder to encoder)
What each wire means:
The internal wiring diagram will represent the following - logically:
As for the current flow direction:
In terms of circuit switch equivalence:
When the transistor is open:
When the transistor is closed:
On the PLC (or other controller) side: these are the typical wiring connections:
Finally, the full wiring layout diagram, connecting the encoder to the PLC:
Additional Resources:
https://www.maxwell-fa.com/incremental-encoder-raspberry-pi-ttl-incremental-encoder_p90.html
https://www.robotics.org.za/CN3806-AB-600N
https://mitsubishielectric.in/fa/GOC43/assets/Graphic%20Operation%20Controller%20User%20Manual.pdf
Drawing file: attached NPN Encoder Connection.drawio (44.4 KB) (drawIO required)
NOTE: Read the wiring connection instructions, installation instructions and operational instructions of your PLC and Encoder carefully, before wiring.