spindle speed backwards?

Edit: This was solved by inverting the Spindle PWM pin. No idea WHY that worked, as the output is a PWM signal to create an analog voltage, but... a'ight... working is working.

NOW I'm having problems with setting up the scaling. I really only need 0-2.5V on the output for my speed control. I'm setting up PWM1 to 0 and PWM2 to 0.25... but then I get nothing on the output, whereas I WAS getting 0-10V output with a test case.





Hello!

First... Thanks for LinuxCNC! I've been using it for years on homebrew machines.

I finally got around to getting a spindle instead of a router.

I wanted to test generic voltages out on my breakout board for spindle speed control. My spindle just needs an analog voltage for speed control. Cool. So...

I set speed 1 to 0, PWM 1 to 0.
I set speed 2 to 1000, PWM2 to 1.

Just like the documentation said to do.

S500, measures about 5v out on my breakout board, which should go 0-10v. Great!

When I increase the speed (s500, s600, s700) the voltage is going.... down?
When I decrease the speed (s400, s300, s200) the voltage is going up.

I am under the impression that this is supposed to be the other way around? Low voltage, low speed, high voltage, high speed.

What am I missing?

just for shitsngiggles, I reversed the order, trying to go from PWM1 of 1 to PWM2 of 0. That didn't work...

PWM rate is set to 100Hz, per documentation for the board.

Easiest way.
SUM2 with negative maxvalue inverts inputvalue
Mike

Uhh.... Can you... give just the slightest bit more context?

Take your commanded value ( before input into probably into pwmgen.x.value) as input for
Setp sum2.x.in0 - 1
Setp mult2.x.in0 - 1
Net xxx1name (your signal) -> sum2.x.in1
Net xxx2name sum2.x.out -> mult2.x. in1
Net xxx3name mult2.x.out -> pwmgen.x.value

Mike

Andypugh suggested "Try inverting the PWM pin".

That worked... heh. Thanks though!