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Offline TFT

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Couple questions about Limit and Home switches
« on: April 08, 2016, 04:30:24 PM »
I'm trying to set up my limit and home switches.

I have installed two limit switches at the upper and lower bounds of my z-axis

They are daisy chained and wired normally on and connected to pin 10.

Under Config/Ports and Pins/Inputs  I have enabled Z++ Z-- Zhome and set them all to pin 10.

When I look at the diagnostics page, all three inputs light up if a hit either of the switches.



Firstly how do i override the limit switch once the spindle hits it?  At this point I have to disable the inputs then reset, then jog off the limit then re enable the inputs.

And Secondly, when I try to reference home the limit switch is triggered and the whole operation stops when the manual clearly says "during referencing limits do not apply".

Am i setting this up correctly?  Can i use the same pin for both Z limits and Z home?

Re: Couple questions about Limit and Home switches
« Reply #1 on: April 10, 2016, 06:45:45 AM »
Quote
Firstly how do i override the limit switch once the spindle hits it?

  Try hitting the R button on the keyboard when this happens.

Quote
Can i use the same pin for both Z limits and Z home?

  this should not be a problem.


What version of Mach3 are you using?
Regards
Charlie M.

Offline Hood

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Re: Couple questions about Limit and Home switches
« Reply #2 on: April 10, 2016, 06:59:26 AM »
If your limits are being triggered when homing then it sounds like poor quality switches that are bouncing.
What should happen when Mach homes is-
The machine moves to the switch, the switch opens, Mach reverses until the switch again closes and then the axis stops and Mach sets that as Home.
If your switches are not good then as Mach reverses the contacts in the switch may close momentarily and then open again, this will make Mach see the close and set home but when it bounces open again Mach will see that and think it is a limit being triggered.

You can try going to General Config page and using some Debounce Interval, try 2000 and see if it helps, if it does lower until you get the lowest value without causing issues.

Ideally however you would want to get better quality switches.

If that is not your problem then attach your xml so I can see how you have things set up.
Hood

Offline TFT

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Re: Couple questions about Limit and Home switches
« Reply #3 on: April 12, 2016, 01:55:17 PM »
 
Quote
Try hitting the R button on the keyboard when this happens.

That did not seem to work.  I still have to go back and disable the imputs to jog off the limit switch.

I'm using Mach3 R3.043.066


You can try going to General Config page and using some Debounce Interval, try 2000 and see if it helps, if it does lower until you get the lowest value without causing issues.

Ideally however you would want to get better quality switches.

If that is not your problem then attach your xml so I can see how you have things set up.
Hood

Setting the de bounce worked, it now finds home and then move's off the switch.  Thanks.  Now if it could do that on the opposite end when it hits the other limit switch that would be nice.

Offline Davek0974

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Re: Couple questions about Limit and Home switches
« Reply #4 on: April 12, 2016, 02:12:24 PM »
 
Setting the de bounce worked, it now finds home and then move's off the switch.  Thanks.  Now if it could do that on the opposite end when it hits the other limit switch that would be nice.


Get your soft-limits setup and you won't hit the far limit swiches ;)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Couple questions about Limit and Home switches
« Reply #5 on: April 12, 2016, 02:16:33 PM »
Also to Reset after you hit a limit you can go to settings page and press the Manual  Limit Override button, you will then be able to jog off after you press Reset.
Better still is the Auto Limit Override button on the same page, means you will just be able to press Reset and not have to press anything else.

As Dave says setting Soft Limits is also a wise move.
Hood

Offline TFT

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Re: Couple questions about Limit and Home switches
« Reply #6 on: April 13, 2016, 12:42:18 PM »
Also to Reset after you hit a limit you can go to settings page and press the Manual  Limit Override button, you will then be able to jog off after you press Reset.
Better still is the Auto Limit Override button on the same page, means you will just be able to press Reset and not have to press anything else.

As Dave says setting Soft Limits is also a wise move.
Hood

Ok the Manual Limit Override button worked, thanks.

For the soft limits, I enabled them for my Y and Z axis and both are sitting at the machine zero coordinates, however I am still getting this error "Machine out of limits for SoftLimit Activation" when i press the soft limit button.  do you have any idea why it would say this?

Offline Davek0974

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Re: Couple questions about Limit and Home switches
« Reply #7 on: April 13, 2016, 02:19:42 PM »
Yes - the machine is in a position that argues with your soft limits settings :)

with my machine axes at bottom left and X & Y homed, machine co-ordianates will now be X0 / Y0, soft limits min is X0 / Y0 and slow-down zone is 15mm on both. X max is 348mm Y max is 448mm, my limit switches are at X 350mm and Y 450mm

With this setting I can zoom around the table and it is impossible to hit a limit switch, as long as the table is homed first.

Z is a little different as home is fully up and Z0, so soft limit Z min is now -150mm and Z max is 0mm.

Tune the slow-down to suit your table - speeds will affect the size of the zone needed to slow enough at full rapid jog speed.

Once set, jog to a mid position, enable soft-limits and should be good to go.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Hood

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Re: Couple questions about Limit and Home switches
« Reply #8 on: April 15, 2016, 10:09:07 AM »
Personally I use the Auto Limit Override as it means you don't have to go to the Settings page each time.

Hood

Offline TFT

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Re: Couple questions about Limit and Home switches
« Reply #9 on: April 15, 2016, 01:28:37 PM »
Personally I use the Auto Limit Override as it means you don't have to go to the Settings page each time.

Hood

yeah.  I think ill do that.