Index pin for spindle what is it looking for.

I have mesa 7i33 card on my lathe.

The spindle encoder is an open collector encoder. I hold the pin high with 1k resistors tied to +5 volts.

I get 1 pulse from the z output on the encoder per revolution. It is a pulse from high(+5) to low(gnd).

what is the index pin in linuxcnc looking for, a low(gnd) to high(+5), or a high(+5) to low(gnd)?

If it is looking for low(gnd) to high(+5) will the invert index pin give the desired output for linuxcnc spindle index.


Jim

Pretty sure that should work as is.

The 7I33 inverts all encoder interface signals so your encoder active low index gets
inverted to a active high index at the FPGA pin (and active high is the default FPGA index polarity)

An easy way to test is unlink the encoder index-enable pin if anything is connected to it
and then setp it true using the machine/show hal configuration/show menu and then
watch the index-enable pin. If you slowly turn the spindle, index-enable pin should get
cleared when the index position is passed. If it gets cleared with any motion,
the index polarity is probably wrong, if it never gets cleared, the index is not
being seen.

Looks like "/encx2" enable is what it was looking for. I only get 1 trip per revolution when hooked up like this.

Thanks.