MPG 7i76 mesa

This should work as mpg on a 7i76 in mode 2?

yep

When I tie the 0v to field power gnd It ceases to work. no error and when I restart linuxcnc I get no 5i25 in HAL calibration., but linuxcnc still starts up and when I neable drive nothing happens. This is really bizarre, linuxcnc should spit an error when it doesnt see the 5i25.

The mpg I cannot to count properly anyway. So I tried tieing the gnd 5 v to field power ground and it doesn't like it.,

IT has me on this one.

I'll try connecting field power 12vdc and see if I get 2.5-5 out of the mpg

Without any hal connections, I should still see it count with the enc correct?

I got it working with 12vdc. I guess the 5v is too close to the 2.5 threshold.

Anyway enc1 is counting.

The 7I76 MPG inputs are 2.5V nominal but have 10% hysteresis so
must be driven above 3V and below 2V to operate correctly

PCW wrote:

The 7I76 MPG inputs are 2.5V nominal but have 10% hysteresis so
must be driven above 3V and below 2V to operate correctly

Is that with all the encoder inputs on the 7i76?

Will it take 12volt pulses? Cause with my thc the encoding is not really stable. I am thinking it is not reaching the threshold all the time.

No, the standard 7I76 (high speed) encoder input is 5V only
If set for TTL mode, the input threshold is 1.6V.

If set for differential mode, the input threshold is ~200 mV differential
with a -7 to +12V common mode range. The THC has differential outputs
and should normally be used with a differential encoder input
(and will drive about differential 3V into the terminated encoder inputs)