Topics

1

Mach4 General Discussion / Issues with VistaCNC P2-S USB pendant and Mach4

« on: November 27, 2018, 04:27:44 PM »

I have a new VistaCNC P2-S USB pendant. I have updated the firmware and it shows "imach4" on the pendant. I am however having stability issues with Mach4 and this pendant. When I use the jog wheel and reverse direction (usually small increments) I find that the system becomes unstable. Basically no matter what axis I jog it then starts sending steps to the axis under command and another axis. If I jog say my X and do a small increment on the wheel (one notch) and reverse direction, it moves rapidly back and forth (once - like a hiccup) and then also sends tiny uncommanded steps to my Y (or Z). Once Mach4 is in this state I have to restart to get it out of this state of small but scary uncommanded moves. I can see the drives on other axis are receiving steps (led flashes) when this happens.

The plugin is all enabled in Mach4. Although there is no configuration screen despite the plugin entry in the top menu. I'm not sure if this is because it needs configuring elsewhere?

As it stands I only test this pendant with the belts off as it feels unsafe to do it any other way given the issues I have experienced.

Aside from this pendant the system is stable. It never get's into this state without the pendant.

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Mach4 General Discussion / Mach4 and ESS servo motor reverse - not being applied?

« on: December 02, 2017, 05:25:33 PM »

I'm running Mach4 and ESS. 2 of my servos are running in the wrong direction and I would like to correct it. I read that Mach4 has a "reverse" checkbox under the motors tab. I click the reverse for each of the servos running in the wrong direction, "Apply" and restart Mach4, yet the servos still turn in the same wrong direction. Does Mach4 support reversing the servo direction like this?

Any ideas how I would correct this issue?

3

Mach4 General Discussion / Calculating Counts per Unit for Mach 4 in metric

« on: November 28, 2017, 04:58:53 AM »

I'm a complete newbie when it comes to CNC control systems. I'm not 100% sure how to calculate and convert the numbers for Counts per Unit.

Some details:
measurements: metric
motors: servos
encoders: AMT102-V quadrature set at 500 counts
output gear (on ballscrew): 60 tooth
input gear (on servo): 20 tooth
ballscrew pitch: 5mm

I'm really unsure if I have done the math correctly and if I multiple my 500 encoder counts by 4 because they are "quadrature encoders"?

The math:
((output_gear / input_gear) * encoder_count) / screw_pitch = counts_per_inch

Plugging in my numbers:
(60 / 20) * (500 * 4) = 6000
6000 / 5 = 1200

Now, I'm unsure if that is giving me a strange mash of metric and imperial. So my second thought is that the screw pitch may need to be divided by an inch (25.4):

6000 / (25.4/5) = 1181.102

I'm unsure which one is correct? I think that the second calculation (1181) seems more logical as it takes into account the metric screw, but yet I'm still not sure  My Mach 4 is set to metric.