[dsnaith]

Hi,

I have built a 3 axis stepper motor router running Mach3 R3.043.022 and 2010 Screenset and so far, everything works great.

I have just finished setting up a NC physical home switch close to the +ve limit of each axis (there were physical reasons why I had to use the +ve end of the X and Y axes). The home switches are wired to pins 11, 12 and 13 respectively and this is set up in Ports and Pins as Active Low. When the axes are in the middle of the the stroke (ie, well clear of the switches) the diagnostic window in 2010 Screenset show a blank box beside the X Home, Y Home and Z Home input signals. If I trigger each switch manually, the respective box turns green - so I think all my inputs are working. I have Mach3 set up to home in the positive direction and auto zero turned off (although, turning it on does not seem to help).

When I select the Ref X, Y or Z buttons at the top of the screen, the respective axis moves a short distance in the positive direction, then stops well before it reaches the switch and the axis button turns green, suggesting it thinks it has homed successfully.

I have the soft limits set to very large (and small) numbers so it doesn't think it is out of limits.

Any suggestions?

Thanks!

Dave.

[BAMCNC.COM]

Interference?

[dsnaith]

Interference?

I don't think so. I am using physical switches, not proxies, everything is shielded and earthed, and the lights on the diagnostic page are rock stable both on and off.

[ger21]

Noise is triggering your switches.
As a quick test to be sure, increase the debounce on the General Config page to about 20,000 and see if it works. If it does, then noise is your problem.

Also, there's a bug in 3.43.022 that will cause Mach3 to lock up if you use my M6 macros.

[dsnaith]

Noise is triggering your switches.
As a quick test to be sure, increase the debounce on the General Config page to about 20,000 and see if it works. If it does, then noise is your problem.

Also, there's a bug in 3.43.022 that will cause Mach3 to lock up if you use my M6 macros.

Ok, thanks Gerry.

I just smoked my z-axis motor, and by the smell of it, at least part of my controller, so it is going to be a while until I can test this.

Dave.

[dsnaith]

My apologies BAMCNC and thanks again Gerry. I set the debounce to 20,000 and it fixed the problem, so I guess you were both correct in suggesting it was noise. I'll be buggered!

I dropped the debounce until I started having problems again, around 250, and then doubled it to 500 and everything seems to be working well. Thanks again both of you.

Dave.

[ger21]

A lot of people add capacitors to the input pins to filter out the noise, but if a debounce of 500 works, that's not too bad. A lot of people need to use 2000-3000.

[neilw20]

A 100n (0.1) capacitor across a switch is a good idea. This causes a momentary hig current through the contact and helps keep it clean.
Unless you have very low current rated switches, often with gold cross points, they will eventually give problems.