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Emergency stop question

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Emergency stop question

Postby woodworkersbruhaus » Sat Jan 28, 2017 1:00 am

I'm working on the book build and I have a question about wiring an emergency stop. I understand wiring for the mach 3 to acknowledge it has been push, but is there anything wrong with wiring the switch so that it kills everything? I was thinking about routing the incoming power through the switch so when pushed all power would be disconnected.
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Re: Emergency stop question

Postby Awesomeness » Sat Jan 28, 2017 5:29 am

I've wondered about that too as there could be conflicting arguments, but at least theoretically, Mach3 can forcibly stop the motion (using the motors) even faster than it will naturally slow down and stop on its own. Power can also remain in the power supply, even after input power is cut, to where it could continue moving and executing commands for a brief time (I'm not sure how long that is, probably <1s).

It is a good idea to cut power to the spindle, since there can't be any benefit to leaving it running, and nothing will stop it faster than cutting power and letting it slow down.
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Re: Emergency stop question

Postby woodworkersbruhaus » Sat Jan 28, 2017 8:14 pm

I see. I hadn't figured on the power supply issue. The control panel that I'm building will have an outlet for the spindle. My thought process was I could kill power to everything, including the spindle with the e-stop. Maybe I'll just use the switch to stop Mach 3. I have an extra switch that I can install next to the other one to stop the spindle.
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Re: Emergency stop question

Postby kevinl » Mon Jan 30, 2017 4:32 pm

I'm not sure of the design in your e-stop switch but some have options for two sets of wiring.. Double throw type switch where you could e-stop mach3 with one side and cut power to the spindle on the other. just a small issue with maybe have 110 volts AC and 5 or 24 control volts DC to mach3 mixed in the same box..

just one thought, I personally like having mach3 stopping the stepper motors, I think that's quicker than coasting to a stop.. if your machine was chain or rack/pinion, a e-stop power removal would have the gantry in a freewheel state which might not have the result one might be looking for or expected..
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Re: Emergency stop question

Postby woodworkersbruhaus » Tue Jan 31, 2017 2:10 am

I could do that, actually. I wouldn't run the low voltage and high voltage that close to each other so I could put in a relay that would stop the spindle. I could utilize the low voltage to supply the coil.
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