SmoothStepper + SuperPID

[jharvey407]

I installed my SmoothStepper today, and everything is working properly, except my SuperPID. The router turn on with M3 but only runs at the lowest speed and does not seem to be receiving the PWM signal from Mach3.

Here is what I have.

SmoothStepper + C10 BOB from CNC4PC + SuperPID

Everything was working fine before I installed the SmoothStepper.

I'm sure it must be a configuration error.

Any ideas what I should be looking at? I need to get this machine up and running for a job Monday morning.

Thanks,
James

[ger21]

I don't use a Smoothstepper, but looking in the manual, it appears there's a checkbox to enable PWM. So you have it checked? Page 22
http://warp9td.com/documentation/Smo...ManualV1.0.pdf

[jharvey407]

I don't use a Smoothstepper, but looking in the manual, it appears there's a checkbox to enable PWM. So you have it checked? Page 22
http://warp9td.com/documentation/Smo...ManualV1.0.pdf

Yes it is checked. I left the base hz at 1000.

[jharvey407]

Here is some more info. I opened the data monitor window. In the spindle box, the PWM mode checkbox is checked. With the spindle off, the ratio is 0, Vel is 0 and ACC is 0.

Currently in Mach my spindle speed is set to 16000. When I use the M3 command or the Spindle start button on the screen the spindle starts and runs at 5000 rpm according to the display on the SuperPID. The data window reports ratio is 0.5315, Vel is 2283039, Acc 0.

Any thoughts on what might be the problem?

To me it seems that the pulses are not reaching the SuperPID. I will continue trouble shooting and check back in a bit.

[ger21]

If you adjust the spindle override slider, does the rpm change?
Try typing S15000 in the MDI. Does that change?

[jharvey407]

If you adjust the spindle override slider, does the rpm change?
Try typing S15000 in the MDI. Does that change?

The actual speed of the spindle remains at 5000 rpm regardless of S command or spindle speed override.

Can you verify my Mach setup?

Motor Outputs - Spindle - Step Pin# - 1
Motor Outputs - Spindle - Dir Pin# - 0

Output Signals - Output #1 - Port# - 1 - Pin Number - 14

Spindle Setup - Relay Control - Disable - Unchecked - Output # - 1

This has been working before the addition of the SmoothStepper. I am reading through the Mach manual right now to verify the setup.

**** A new development ****

I just switched the Step Pin to LowActive - now the router runs at full speed with no control instead of min speed with no controll.

[ger21]

Do you have "Use Spindle Motor Output" and "PWM Control" checked on the Spindle Setup Tab?

[jharvey407]

Do you have "Use Spindle Motor Output" and "PWM Control" checked on the Spindle Setup Tab?

Yes. PWMBase Freq. 35. Kernel Speed 35000 Hz.

[jharvey407]

I'm on the right track now.

On a whim I decided to put a value in the Spindle Motor Movement Profile. I just slid the Velocity slider up a bit, ending up with the random In's per min of 534180.

The spindle is now responding to PWM control.

At this point I have no idea how the Spindle Profile will affect the PWM control so I'll do some experimenting and report back.

[Larken]

Is it documented anywhere how to setup the PWM for Mach3?

It sort of works, but its non-linear at the bottom and does't seem to respond to the min and max rpm right.

I wonder why he put a min pwm setting, since for PWM it should be able to go from 0-100% linearly.

[ger21]

It is linear from 0-100%.
The minimum setting is a safety to prevent you from running your spindle too slow.

PWM Control
A PWM signal is a digital signal, a "square" wave where the percentage of the time the
signal is high specifies the percentage of the full speed of the motor at which it should run So, suppose you have a motor and PWM drive with maximum speed of 3000 rpm then
figure 4.12 would run the motor at 3000 x 0.2 = 600 RPM. Similarly the signal in figure
4.13 would run it at 1500 RPM.

Mach3 has to make a trade off in how many different widths of pulse it can produce again how high a frequency the square wave can be. If the frequency is 5 Hz the Mach3 running with a 25000 Hz kernel speed can output 5000 different speeds. Moving to 10Hz reduces this to 2500 different speeds but this still amounts to a resolution of one or two RPM.

A low frequency of square wave increases the time that it will take for the motor drive to notice that a speed change has been requested. Between 5 and 10 Hz gives a good compromise. The chosen frequency is entered in the PWMBase Freq box.

Many drives and motors have a minimum speed. Typically because the cooling fan is very inefficient at low speeds whereas high torque and current might still be demanded. The Minimum PWM % box allows you to set the percentage of maximum speed at which Mach will stop outputting the PWM signal.

You should be aware that the PWM drive electronics may also have a minimum speed setting and that Mach3 pulley configuration (see section x.x) allows you to set minimum speeds. Typically you should aim to set the pulley limit slightly higher than the Minimum PWM % or hardware limit as this will clip the speed and/or give a sensible error message rather than just stopping it.

[Al_The_Man]

What was the reason going PWM I wonder? There is an option for step/dir spindle, the signal has to be converted to analog for SuperPID and VFD's anyway.
A frequency to analogue circuit I would think is the simpler way to go?
Al.