Interface/protocol to encoder on Panasonic servo motor

[richardhsewell]

Anyone know anything about the protocol used to interface to the rotary encoder in a Panasonic industrial servo motor? (MINAS A5 series, MSME). It is a 20 bit incremental encoder and has 5V/GND/PS/PS(NOT) connections. I was expecting this to be a regular quadrature encoder, but this seems to be a proprietary serial interface, with a bunch of chips (MNM 1222??) inside the encoder to support.
Only information I can find is a short discussion which goes nowhere here https://www.physicsforums.com/threads/panasonic-incremental-encoder.879929/

Was hoping to use some of these as input devices for a jog-wheel type application. Just spent ages figuring out the quadrature hardware module on the pocketbeagle, which I may still have to use but with a different encoder.

[OM222O]

What does the waveform look like? For any reverse engineering project you shouold start there. Post waveforms of both going forward and reverse.

[capt bullshot]

The Japanese drives have a bunch of more or less proprietary protocols. Don't know what Panasonic actually uses, but Tamagawa and A-Format come to my mind.

There's a thread regarding this topic :
https://www.eevblog.com/forum/projects/familiar-with-fanuc-servo-drives-reverse-engineering-serial-encoder/msg3045986/#msg3045986

[richardhsewell]

Thanks for the link to the discussion capt' , that's sort of what I was looking for to give me a sense of what I'm dealing with here. Looks like this would be fairly challenging reverse engineering project starting from scratch and may require an FPGA to interface to the signal. That's more than I want to take on for this project when the alternative is to just use a regular optical quadrature encoder. Bit of a shame 'cause these are very high precision encoders with some nice tech inside them (and I'm getting them free from a machine pull).

[smooker]

2.5MBps RZ 8N1 RS485
0x52 comes from drive - seems encoder reset.
changes afterwards to 0x2a - read encoder command

[grkmgry]

seems to respond to the following commands. but I could not find a protocol that fits these commands. it is not compatible with the standard tamagawa protocol.
0x2A
0x4A
0x52
0x7A
0xA2
0xDA
0xF2