Hello Guest it is August 17, 2019, 07:24:41 PM

Author Topic: New to site - Mach3 homing support needed  (Read 484 times)

0 Members and 1 Guest are viewing this topic.

Offline TPS

*
  •  1,375 1,375
    • View Profile
Re: New to site - Mach3 homing support needed
« Reply #10 on: January 07, 2019, 04:45:30 AM »
ok that is a normal PP BoB.

can you post some screenshots of your motortunig Screens.
maybe your acceleration is so "soft" that the axis is not able to stop on the Limit Switch ?
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: New to site - Mach3 homing support needed
« Reply #11 on: January 11, 2019, 05:57:38 AM »
just a thought, if you are using the same switches for homing and limits, make sure the ports and pins page is set up to reflect this.
Do you have individual pins assigned to each or are they all going to one pin?
Re: New to site - Mach3 homing support needed
« Reply #12 on: January 11, 2019, 06:18:28 AM »
maybe your acceleration is so "soft" that the axis is not able to stop on the Limit Switch ?

What do you mean with "soft" in the above context  ??

Thomss
Re: New to site - Mach3 homing support needed
« Reply #13 on: January 11, 2019, 06:41:27 AM »
I think this means that the acceleration/decelleration values are so low that it hits the limit switch and overruns due to the motor's programmed wind-down rate.
With this said Mach3 treats limit switches and home switches differently, hitting a limit should trigger a hard emergency stop but a home switch just acts as part of the homing process and won't interrupt anything.
Is it possible on your machine for the actuator to climb over the switch and release it before the motor has finished slowing down? I've never had this condition but it might cause wierd homing. Have a look at it and see if you can keep the home switch held as long as possible, raise the motor acceleration slightly or slow it down a little if this is a possibility.

Offline TPS

*
  •  1,375 1,375
    • View Profile
Re: New to site - Mach3 homing support needed
« Reply #14 on: January 11, 2019, 06:50:59 AM »
normal home procedure is:

1.go towards Limit Switch until Limit Switch is hit
2.then ramp down with Motortuning->ACC
3.then go with lower Speed in reverse direction until Limit Switch is free

so if the rampdown pt.2. is to "soft" (low) and the Motor is not able to stop within the range the Limit Switch is
enabled (goes over the Limit Switch), then is in pt.3 the Limit Switch allready free again and it will finish
without reversing.

excuse my bad english
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: New to site - Mach3 homing support needed
« Reply #15 on: January 11, 2019, 06:52:15 AM »
^ that's it exactly

Offline TPS

*
  •  1,375 1,375
    • View Profile
Re: New to site - Mach3 homing support needed
« Reply #16 on: January 11, 2019, 06:56:23 AM »
maybe you can post
-a screenshot of your motortuning
-a screenshot of Homing/Limits
-a photo of the fixture from the Limit switch
anything is possible, just try it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: New to site - Mach3 homing support needed
« Reply #17 on: January 11, 2019, 03:59:45 PM »
Response to the home switches became erratic and the DRO would Zero occasionally when the switches were activated and not other times.
In order to eliminate the break out board I ground the pins on the parallel cable where it plugs into the BOB and simulated switch actuation at that point hoping to eliminate a number of variables.
When the symptom persisted I concluded the BOB was not at fault and the cause lay elsewhere.
Checked the BOB XML file size in the Mach3 directory it was not the same as supplied by the manufacturer so it was reloaded/reconfigured and all appears to be working as it should (and as described by TPS in his post).
System now homes as required when pressing 'Ref All Home', just need to sort out some additional settings and we should be good to go.
I'm retrofitting and old Gravograph engraving machine and by design it homes X at 0, Y at the top of its movement range and Z also at the top (as is the case with other mill set ups).
Will sort out settings for Y axis, offsets G55 etc. next.
Steep learning curve but interesting none the less.
Many thanks to all for your suggestions, no doubt will have more questions in the future.
Regards,

John

Offline lesmg

*
  •  11 11
    • View Profile
Re: New to site - Mach3 homing support needed
« Reply #18 on: January 16, 2019, 10:07:07 AM »
I set my debounce to 8000 and also added

while IsMoving
Wend
Code "G53 G0 X10"
Code "G53 G0 Y10"
While IsMoving
Wend

so it moves the gantry clear of the switch

Les