Limit / Home Switch
29 Dec 2016 00:16 #84825
by dextaca
Limit / Home Switch was created by dextaca
Gents / ladies. Just a quick one .
Any suggestion on how I could wire a 2 switch limit / home switch ( Omron limit switch VB-2121) to work with 3 wire systems ( Linux CNC) ?
Regards
Peter
Any suggestion on how I could wire a 2 switch limit / home switch ( Omron limit switch VB-2121) to work with 3 wire systems ( Linux CNC) ?
Regards
Peter
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29 Dec 2016 01:38 #84831
by rodw
Replied by rodw on topic Limit / Home Switch
I think one of them would be set as a shared home/limit switch and the other to operate as an independent limit switch.
linuxcnc.org/docs/html/config/ini-homing.html
Just make sure your HOME_OFFSET moves the axis far enough to clear the switch or you will get a limit error once the homing sequence is completed.
linuxcnc.org/docs/html/config/ini-homing.html
Just make sure your HOME_OFFSET moves the axis far enough to clear the switch or you will get a limit error once the homing sequence is completed.
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01 Jan 2017 01:07 #84979
by andypugh
Replied by andypugh on topic Limit / Home Switch
I am not sure that I understand the question.
Are you saying that you have 2-wire limit switches and you want to combine them to use a single digital input?
Are you saying that you have 2-wire limit switches and you want to combine them to use a single digital input?
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01 Jan 2017 12:53 #85000
by dextaca
Replied by dextaca on topic Limit / Home Switch
Sorry I guess my explication is a bit crude.. Fanuc 0M mills have only 2 switches (Omron limit switch VB-2121) one switch acts as a pos / neg switch ,as home switch.. Problem is that I have a new servo retrofit ( Yaskawa that needs pos / neg switch , then I need a 3rd switch or a way of sharing one limit switch as a home for LinuxCNC? Any suggestion?
Details is that if I tyake the falling edge as high.. the servopacks block and will not overtravel until low...
that's my dillema..
Details is that if I tyake the falling edge as high.. the servopacks block and will not overtravel until low...
that's my dillema..
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01 Jan 2017 12:58 #85001
by andypugh
Replied by andypugh on topic Limit / Home Switch
It is quite usual for all home and limit switches to be entirely controlled by LinuxCNC and to not have a hardwired connection to the drives. So the simple answer might be to simply not wire the limits to the drives.
If you definitely want to retain hardware limit switches then you could consider a LinuxCNC-controlled relay to bypass the limit switch during the homing sequence.
If you definitely want to retain hardware limit switches then you could consider a LinuxCNC-controlled relay to bypass the limit switch during the homing sequence.
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01 Jan 2017 13:08 #85002
by rodw
Replied by rodw on topic Limit / Home Switch
If you take Andys suggestion and not wire the limits to the drives, then if you follow these instructions
linuxcnc.org/docs/html/config/ini-homing.html
You will end up with something like this in your .ini file on the axis with the shared home/limit switch
linuxcnc.org/docs/html/config/ini-homing.html
You will end up with something like this in your .ini file on the axis with the shared home/limit switch
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = -10
HOME_LATCH_VEL = 5
HOME_FINAL_VEL = 10
HOME_USE_INDEX = NO
HOME_SEQUENCE = 0
HOME_IS_SHARED = 1Please Log in or Create an account to join the conversation.
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