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	wiring home switch and index to PP
- mikeT
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						13 Sep 2021 15:16				#220447
		by mikeT
	
	
		
			
	
			
			 		
													
	
				wiring home switch and index to PP was created by mikeT			
			
				I have both home switches and index switches on the X and Y axes on my mill. How do I connect them to the parallel port. Can it be done through stepconfig?
Thanks for your hep and advice
MikeT
					Thanks for your hep and advice
MikeT
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						13 Sep 2021 18:09				#220479
		by mikeT
	
	
		
			
	
			
			 		
													
	
				Replied by mikeT on topic wiring home switch and index to PP			
			
				Stepconfig will allow me to allocate ONE home switch to the X and Y axes. I wish to allocate a home switch PLUS a index switch to the each of the X and Y axes. I am looking for help and advise on how to do this.
Thanks
MikeT
					Thanks
MikeT
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- tommylight
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						13 Sep 2021 21:34				#220510
		by tommylight
	
	
		
			
	
	
			 		
													
	
				Replied by tommylight on topic wiring home switch and index to PP			
			
				Most probably it can be done, but i fail to comprehend why would you use 2 switches for the same thing, it will not help with homing precision. Index homing is used for servo systems to always home at the same motor position.
Uses
home_use_index = 1
in the .INI file, but it should also have an entry in the .HAL file connecting the input with the index pin.
					Uses
home_use_index = 1
in the .INI file, but it should also have an entry in the .HAL file connecting the input with the index pin.
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						13 Sep 2021 21:55		 -  13 Sep 2021 22:52		#220516
		by mikeT
	
	
		
			
	
	
			 		
													
	
				Replied by mikeT on topic wiring home switch and index to PP			
			
				Thanks for getting back.
I have been told?? that a home switch plus an index switch will give higher homing precision than a home switch alone. Any switch timing/position error would be significantly smaller on the faster index disc movement, than on the slower carriage movement.
My machine is a modified EMCO VMC, now running on LinuxCNC. It uses steppers, not servos and has both magnetic home switches and magnetic index switches installed. They must have done that for a good reason
Thanks again for you help
MikeT
					I have been told?? that a home switch plus an index switch will give higher homing precision than a home switch alone. Any switch timing/position error would be significantly smaller on the faster index disc movement, than on the slower carriage movement.
My machine is a modified EMCO VMC, now running on LinuxCNC. It uses steppers, not servos and has both magnetic home switches and magnetic index switches installed. They must have done that for a good reason
Thanks again for you help
MikeT
		Last edit: 13 Sep 2021 22:52  by mikeT.			
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						13 Sep 2021 23:02				#220526
		by tommylight
	
	
		
			
	
	
			 		
													
	
				Replied by tommylight on topic wiring home switch and index to PP			
			
				Are the indexes on the motors or near the home switches?
If near the home switches, they are home and limit switches, but LinuxCNC does not require that, it can use the same switch for home and limit.
					If near the home switches, they are home and limit switches, but LinuxCNC does not require that, it can use the same switch for home and limit.
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						14 Sep 2021 09:32				#220567
		by mikeT
	
	
		
			
	
			
			 		
													
	
				Replied by mikeT on topic wiring home switch and index to PP			
			
				Thank you tommylight for showing an interest.
The 'home' switch is tripped by the table as it approaches end of travel. The 'index' switch is tripped, once per revolution, by the pulley on the leadscrew; that's every 4. 0 mm of travel.
I assume that homing is done at rapid speed until the 'home' switch is tripped (course homing) and then at slower speed until the next 'index' switch is tripped for fine homing.
I know nothing about the accuracy and repeatability of the magnetic switches, so can only assume they were adequate; neither good or bad.
It's definitely two switch homing
Miket
					The 'home' switch is tripped by the table as it approaches end of travel. The 'index' switch is tripped, once per revolution, by the pulley on the leadscrew; that's every 4. 0 mm of travel.
I assume that homing is done at rapid speed until the 'home' switch is tripped (course homing) and then at slower speed until the next 'index' switch is tripped for fine homing.
I know nothing about the accuracy and repeatability of the magnetic switches, so can only assume they were adequate; neither good or bad.
It's definitely two switch homing
Miket
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						14 Sep 2021 09:38				#220568
		by tommylight
	
	
		
			
	
	
			 		
													
	
				Replied by tommylight on topic wiring home switch and index to PP			
			
				OK that is the case when index is useful, so have a look at the docs, homing section should have info on index use and setup for sure.
On phone so cant do much.
					On phone so cant do much.
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						14 Sep 2021 10:04		 -  14 Sep 2021 11:02		#220570
		by mikeT
	
	
		
			
	
	
			 		
													
	
				Replied by mikeT on topic wiring home switch and index to PP			
			
				The homing section in the docs talks only about index use and the ini settings.
I am still trying to find a way to connect the switches to the parport.
It looks like I will need to change the hal as well.
It's getting to be a bit beyond my pay scale. Think I'm gonna need some help on this one
MikeT
					I am still trying to find a way to connect the switches to the parport.
It looks like I will need to change the hal as well.
It's getting to be a bit beyond my pay scale. Think I'm gonna need some help on this one
MikeT
		Last edit: 14 Sep 2021 11:02  by mikeT.			
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						14 Sep 2021 14:31				#220602
		by Clive S
	
	
		
			
				
					
	
			
			 		
													
	
				Replied by Clive S on topic wiring home switch and index to PP			
			I think its time to post your hal and ini files and the version of Linuxcnc that you are usingThe homing section in the docs talks only about index use and the ini settings.
I am still trying to find a way to connect the switches to the parport.
It looks like I will need to change the hal as well.
It's getting to be a bit beyond my pay scale. Think I'm gonna need some help on this one
MikeT
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						14 Sep 2021 15:29				#220613
		by mikeT
	
	
		
			
	
			
			 		
													
	
				Replied by mikeT on topic wiring home switch and index to PP			
			
				Hello Clive,
Thanks for taking an interest.
My ini and hal files are as delivered on the 2.7.0 distro.
I have made no changes and have not yet connected any limits and index switches. Not until I know what to do.
MikeT
					Thanks for taking an interest.
My ini and hal files are as delivered on the 2.7.0 distro.
I have made no changes and have not yet connected any limits and index switches. Not until I know what to do.
MikeT
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