Encoder on spindle question

Hello everyone,
I have been using mach3 for a while on a couple of different machines. I
recently bought a Spectralight cnc lathe that has a Sherline at its core.
I was able to get the steppers working by adding G-251 geckos and a C-10
breakout board.
I am trying to get the spindle encoder to talk to Mach.
The encoder is a US Digital E5-500-315-1A, and it is mounted to the side
of the spindle and driven with a timing belt at about a 4 or 5 to 1 step
up ratio. (The encoder turns 4 or 5 time faster than the spindle.)
The encoder pin out is:
1 ground
2 index
3 channel A
4 +5V
5 channel B

Using 5v from the breakout board (which is USB powered from the
computer) my fluke multimeter can read HZ and shows output on both
channels of up to 82KHZ at max speed and the index reads around 150HZ in
mid range and drops lower at Max speed.
The lathe came with an adapter board attached to the encoder that seems
to multiply the index output to match the a/b output frequency. I have
removed it, but can use it if needed.

If I use the index, Mach never sees it. If I use either channel, the
index light (on the diagnostics page of Mach3 turn) will pulse slowly.

The spindle speed dro stays at 0. Do I need to turn it on somewhere?

I am guessing the pulse width is too narrow for mach to read. My
thoughts for a cure are to add a couple of decade counter chips to
divide by 40 or so.

I'd like to use the existing encoder, but as a last resort I will remove
it and install a SB5B to give one pulse per rev.

Thanks for any help!

--


Ron Thompson
On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA

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