On 04/22/2021 11:23 PM, andrew beck wrote:
update on encoder splitting to altivar vfd and mesa card
hey guys just a update and a few more questions
so I managed to get the encoder mounted on my spindle and working fine.
the vfd works in closed loop control now and I get quite nice power control
at almost zero rpm its great actually.
now I need to get that encoder output into my mesa card
the encoder I have can have any voltage from 5/25 and output equals input.
the vfd senses low state at under 1.5 and high state at over 7.7v
the vfd sends 12v out into encoder currently
so my plan is to just put a resistor in series on the 12 v out to encoder
to bring the power down to 10v or so. then the mesa ency card will work I
think and I can split off the feedback to the mesa card and get the
orientation in linuxcnc working and rigid tapping.
so big question is what value of resistor do i need to bring the volts down
a bit.
Well, connecting the VFD into the mix may bring in a lot of
noise.
Does the Mesa board have a load resistor at the input?
I don't think a simple series resistor is going to work.
Possibly a
pair of resistors in a voltage divider network would work.
First, make sure
the ground on the 12 V supply to the encoder is really at
ground with respect
to the Mesa card. If not, you will either need to solve
that or use opto-isolators.
If the ground is fine, then maybe a 10 K Ohm resistor from
each encoder signal
to the Mesa input and a 4.7 K from Mesa input to ground will
work.
You might have to adjust the resistor values to get good
high and low voltages at
the Mesa input.
Jon
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
