Machsupport Forum

Mach Discussion => Mach4 General Discussion => Topic started by: Pompus on May 21, 2020, 10:16:26 AM

Title: Startup Logic when sharing switches
Post by: Pompus on May 21, 2020, 10:16:26 AM

I think I understand the logic when sharing a + and - limit switch on the same axis. When the software tells the machine to move in the - direction and a switch is tripped it knows the - switch was tripped. What happens at startup with on of the switches is tripped? Do you have to physically jog the machine to un-trip any tripped switch or is there some logic I'm not understanding?

I'm currently working on a six axis robot and would like to run as few wires as possible.

Thanks for any help.

Title: Re: Startup Logic when sharing switches
Post by: Steve Stallings on May 21, 2020, 12:48:03 PM

If you start up a machine with a limit switch activated and are configured to share the input for that switch with another limit switch, you will need to use the "Axis Limits Override" button on the jogging panel on screen in order to allow you to jog away from the switch that is activated. After that the normal homing should work.

Title: Re: Startup Logic when sharing switches
Post by: Pompus on May 21, 2020, 02:25:30 PM

Thanks Steve....

I guess the only automated way would be to wire each switch separately.

Title: Re: Startup Logic when sharing switches
Post by: joeaverage on May 21, 2020, 02:54:11 PM

Hi,

Quote

I guess the only automated way would be to wire each switch separately.

Yes, unless you are absolutely constrained as to the number of separate inputs then one limit per input, one home
per input is best. Despite the extra wiring is by far and away the least confusing too.

Craig