Re: [CAD_CAM_EDM_DRO] Heidenhain encoder:Trash or Treasure?

Donald Brock wrote:

> I'm in need of some qualified help to determine if I have trash or
> treasure on my hands.
>
> A servo motor was replaced on our shops Fadal VMC some months ago and
> during a shop cleanup two days ago the motor was tossed into the
> dumpster. I recovered the motor from the dumpster and removed the
> encoder from it last night. I have every reason to believe the
> encoder to be fully functional.
>
> The encoder has 12 wires to a PCB connector and is labled as follows:
>
> ROD 426.060B - 8192
> Id. No. 316 590 02
> S. No. 7 100 250 U9(not part of the s. no.)
>
> So far I have been able to determine that it is 5V w/TTL output.
>
> A lookup on the Heidenhain web site give a color code for the 400
> series but the wire color code in the chart doesn't quite match what
> I have here. It does somewhat but not 100%.
>
> There is also not enough info on the web site to tell me how many
> lines the encoder is.

I would guess it is 8192 cycles/rev, or 32768 quadrature counts/rev!
WOW!

>
> Questions are:
>
> Will I be able to make benificial use of this encoder?

Most likely.

>
> Any info on this unit or assistance in how I can hook it up to make
> use of it would be appreciated.

If you can figure out the +5 and ground (look for a few capacitors
connected across these two wires) then you can probably figure
out the rest. With 12 wires, it is most likely differential, with
commutation
signals for brushless motors. You probably have no need of the
commutation signals, they would be the ones that change only a few
times per rev. The A and B quadrature channels would be changing
if you just touch the shaft, at that resolution. The differential lines
of each channel would always be the exact opposite of each other,
so you can figure those pairs out. The last signal is the index, which
only ocurrs once per revolution, as a very short pulse, and is pretty
hard to catch. This accounts for 11 signals. The 12th wire could
be either a fault signal or a shield ground.

Jon