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Author Topic: No PWM from ESS and G540  (Read 4587 times)

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No PWM from ESS and G540
« on: May 29, 2017, 06:14:01 AM »

I am currently trying to retrofit a laser to my 3 axis XYZ bed.
This machine has been up and running as a CNC router for several years now, but its time for a change :-)

I am using mach3 -> smoothstepper (ethernet version) -> G540 motor driver.

I am attempting to use;
output #1 on the G540 to provide power to the laser PSU.
output #2 on the G540 to provide the PWM to the laser driver circuitry to control laser intensity. (I want PWM, not analog voltage).

I have been able to get output #1 working fine, and have had success doing some preliminary cuts (with the laser running at 100%)

No such success with output #2 thou :-(

My setup so far is;

Ports & Pins -> Spindle Setup:
- Disable spindle relays is unchecked
- CW and CCW boxes are output 1
- Use spindle motor output is checked
- PWM control is checked (think ESS overrides this)

Ports & Pins -> Output signals:
- Output #1 is port 2, pin 17
- Output #1 is port 2, pin 1

Ports & Pins -> Motor outputs:
- Spindle enabled. Step pin 1, port 2. Dir fields left as default.

- PWM box is checked
- Base Hz is set to 100.

When I turn on the "spindle", the laser comes on at full power.
Changing the spindle RPM control in mach3 does not appear to do anything.
Neither does G3 S10, G3 S100, etc.
I have verified with an oscilloscope that there is no PWM on output #2 of the G540.

Any help would be awesome, as I have run out of ideas. :-)