Re: DAC to feed rate.

[Tom Freedy <tomf4-at-uniserve.com>]

  Jon,

 I still can't figure this out.
If I want to do a line at 200 IPM, 50% of max (400 IPM)
with output scale at 0.058 to produce a 5v DAC what
would I set acc & vel to to produce this? Or am I missing
something else?

Tom.

Jon Elson wrote:

The standard velocity command signals are historically
+/- 10 V.  So, you would decide the highest velocity the
system is capable of, and make +10 V cause the servo
amp to produce such a velocity.  Then, there are parameters
in the EMC .ini file that set the scale of the DAC, in volts.
There is some description of this in the document
 http://www.isd.mel.nist.gov/projects/emc/emcsoft.html

This computation is in mm/sec, I think.  So that 400 IPM
= 170 mm/sec, and you want 10 V output for that velocity,
I think you would specify :
OUTPUT_SCALE = 0.058 0
This is calculated as 10 V = 170 * scale or
    10 / 170  = scale

Jon