Wiring Optical Speed Sensor to P10 on Acorn Rev3

[DigitalMechanic]

So I have done a lot of searching for _any_ useful description of the pinouts for P10 and all I came up with is on Page 8 of the "ACORN User Guide". I can't seem to find any better description, or any schematics (in the cacophanmy of Acorn_rev3 docs) that descibe anything other than the corner-pin numbers on the port (which has a high "duh" factor for anyone familiar with RS232 protocol)...
I'm trying to see if I can even wire up an Optical Speed Sensor (A050-21936A Optical Quadratic Encoder from Sherline/masso) with: A, B, Z, 24v, and G pins, to the Acorn P10 DB9: N/C, Return, -Index, -A, -B +Index, +A, +B, +5V (pins 1-9 from left to right). I get that I should be powering the sensor 24v from the rail, but sensor's G to Acorn's Chassis Ground? and I believe the A, B, and Z from the sensor alternate +n or -n depending on where they are in relation to the encoder pattern (hence the "quadratic" part), but how are the -n signals wired? or are they just ignored?

BTW: I'm on an extremely austere budget so going out an buy different sensors isn't an option, in which case I'll probably end up just guessing at my Spindle RPM.

Any help or ideas would be greatly appreciated!

Thanks in advance,

-DM

[cncsnw]

No, the Acorn encoder port can only be used to read a 5V differential encoder.

If your encoder-like device requires 24V, and only has one output per channel, then you would have to devise some type of signal converter circuit to install between the device and the Acorn. That circuit would have to supply 24V to the encoder, read the encoder channels, and send out differential line driver channels to Acorn.

See also http://www.cncsnw.com/Quadrature.htm

[suntravel]

Related reading:

viewtopic.php?p=4161&hilit=encoder#p4161

Uwe

[cnckeith]

alternative cheap RPM sensor technique. just for RPM display (not rigid tapping)

viewtopic.php?p=48400#p48400