Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: stemasoft on October 20, 2007, 08:46:29 AM
-
Hi everyone
This year I bought myself the HobbyCNCPro kit and a 3D milling machine.
As operating SW I decided to by Mach3 from Canada. A very useful
Software, off course!
Now everything went perfect until I wanted to set up the home/limit
switches. I'm using them as follows: Xhome/X-- and X++ in series as
well as Yhome/Y-- and y++ in series. At Z axis I'm using Zhome and Z++.
This means I have on X and Y 2 switches in series and in Z 1 switch.
Now according to the Mach3 manual I've set up and activated all inputs.
If I'm looking at the diagnostic page I see the LED lighting up but
nothing happens. Even more I get the message that a limit switch is
triggered. So I disabled all switches and operate the machine with soft
limits. That works but I would like to use those switches.
I use NC switches and all have the same ground at HobbyCNC Pro and I
use the pins 10 (X) 11(Y) 12(Z). At Mach3 active low is not activated.
I own an older version of the 4AUPC Choper Driver kit. If I connect the
same kind of switches there (with or without power on) Mach3 recognises
the switch an stops immediately. May there be a problem with the length
of the cablings. My Maschine has travel in X 950mm and in Y 650mm. The
longest cable may be (Z) over 2m. I'm using shielded cables with .14mm2.
Does anyone have an idea where I would have to look at. ??? ??? ???
I appreciate all your efforts.
Kindly
Martin Steiner
-
Try increasing the debounce on the General Configs page.
Hood
-
I run the same controller and had the same problem made worse by the fact that I shared the motor cable with the limit switches. You need to add some capacitors to the inputs at the control board between eash switch line & ground. I 'think' I used .1 or .01 caps on mine. It solved the problem with the induced noise on the lines and all is well.
-
Thanks Hood for your input. Yesterday evening I tried this but it didn't change anything. But as you may have seen rustyolddog runs the same driverboard and he might have the solution with the capacitors.
Anyway thank you for helping!
-
Hi rustyolldog I'm very happy having found someone who was facing the same problem. That's the reason for why I placed this message in this forum. Next week I will get me some capacitors and try all over again. The result I will report to the forum and as well to Dave Rigotti who supllies those driver boards.
Thanks a lot for your help so far and have a nice day.
Kind regards
Martin
-
Hey Martin, I went back and searched my old posts on another forum from where I was having the problem, note that 5v is all that is neccessary to change the state of the input:
H-CNC board is chopper drive, &
stepper motors are obviously pulse drive. Noisy, trashy stuff. I
included my limit switch wires in the same cable with the motors. I
put my scope on the limit swith leads at the controller board and I
found 3 Vpp of noise on the switch lines.
I put a .01 cap from the lines to ground and viola, noise was gone
and the home switchs worked as designed. I suspect shieled cable for
the home switches would be in order but I'd still use a cap across
any & all of the I/O lines to reduce the chance of a spike tripping
things.
-
Hi Rustyolddog as a matter of fact I'm using shielded cables separately for switches and motors. But still facing this certain problem. As mentioned before I will try with capacitors and see what happens (or not!?). But now as not an electronic specialist where exactely do you put the capacitors in? Ground is clear but than where would I have to hook up the other leg of capacitor. Maybe you can explaine oer send me a sketch by email! Thanks anyway
-
I put mine in right on the connector strip where the wires from your switches go. I used the small monolythic (yellow rectangular kind) between the ground screw and each switch input. Simple, no soldering required.
-
If you say 0,01, do you mean uF, pF or nF for the capacitors?
-
.01 uF
-
Hi rustyolddog
I am vary happy! Your tipp to install those capacitors worked out well. Now my cnc milling machine does as it should!
Many thanks for your support and have a nice Sunday.
Regards
Martin
-
Glad to have helped Martin. When you get a chance, post a pic of your machine.
--C
-
I certainly will do so. Martin
-
Hi Stemasoft,
I Have identical case with 3D-step card. I have shielded lines for stepper motors too; grounded at both ends. 3D-step card has those capasitors already. One interesting notice was that by deactivating - limit or home (with all axis) by sw the problem was gone. Card do not deliver that disturbing signal I believe. I tried to increase debounce to 0.7s but did not help. One idea is that my computer is bit too slow 900MHz and that causes timing issues with mach3. I have plan to make some oscilloscope measurements in near future to ensure that drivercard led's are not too fast to my eyes.
-
Hi rustyolddog
I am vary happy! Your tipp to install those capacitors worked out well. Now my cnc milling machine does as it should!
Many thanks for your support and have a nice Sunday.
Regards
Martin
Dear martin... First af all... Sorry for my ugly english
I need your assitance because I jave the some problem with the mechanical limit switch
I have 3 installed on X, Y and Z axis through shield cable. mach recognise this limits. The machine move all axis manually, but if you load a G code and run Mch3 stop saying Limit Switch Triggered.... The machine works if you shut down the limits.
Could you send me a drawing wit the 0.01 uf capacitor installation ??
Thanks and sorry again for muy english. Seba :)
-
Dont connect the ground at both ends. The ground for the shield should be connected at the controller. It is used to keep stray EMF or signals from being brought in. The connecting at both ends brings the machine gorund and controller ground together. This is the cause of many problems with the HCNC Pro. I have expereinced many issues with this same thing. With probes, touch plates, speed controllers. EVERY TIME. Dave is knowledgable about electronics, he knows how to stop the triggering he just has so many peple who screw up before that. He waits for you to research it a bit on your own. I used a metal case for mine because I had it and I think plastic looked cheap. Anyway that caused all of the triggering problems you refer to and never a diagnostic light showed up. In fact I turned the power off to the controller and ran a gcode and it worked. I knew something was wrong and used a cheap ground adapter and removed the ground momentarily and voila it worked. Check my username and see if you dont see those problems show up. Btw debounce and caps never would help mine til the ground issue was solved.
-
This is why you use opto isolation. Connecting that ground on the machine is causing you the problem.
Hi Stemasoft,
I Have identical case with 3D-step card. I have shielded lines for stepper motors too; grounded at both ends. 3D-step card has those capasitors already. One interesting notice was that by deactivating - limit or home (with all axis) by sw the problem was gone. Card do not deliver that disturbing signal I believe. I tried to increase debounce to 0.7s but did not help. One idea is that my computer is bit too slow 900MHz and that causes timing issues with mach3. I have plan to make some oscilloscope measurements in near future to ensure that drivercard led's are not too fast to my eyes.