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Author Topic: how to hook up a e stop  (Read 6970 times)

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how to hook up a e stop
« on: December 01, 2009, 09:05:04 PM »
Hi this is larry . I have hardly ever asked a Question before . The program is so easy to use as soon as you get it going . But I need to ask one question now. I have whent over some of your post but there is so many of them. I need to know how to hook up my estop so that when I push it it will tell  mach to stop the g code. I now have it hooked to my  cnc interface board. I think it is a 10 cnc for cnc board. Any way all it does is stop the board from runing. What I need to know is there a way to signal the computer. I have had to stop the machine a few times and then run over to the key board and tell it to stop. Then go set the machine and spend the next 2 hours reseting the mahine then the computer. That is if I am lucky. I would really apreciate your help thanks

Offline Hood

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Re: how to hook up a e stop
« Reply #1 on: December 02, 2009, 03:35:08 AM »
I am not sure how the E-Stop input to the breakout board  you have works. Normally however you would have a double pole normally closed E-Stop, one pole would cut the power to your drives (via a contactor) and the other pole would be input to Mach on the E-Stop input.
 It should be noted that when you press the E-Stop (or Stop in Mach) that you will most likely have lost position so a rehome will be needed.
Hood

Offline olf20

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Re: how to hook up a e stop
« Reply #2 on: December 02, 2009, 07:03:08 AM »
Are you wanting to just pause the program???
If so the FEED HOLD will do just that. When you want to restart
the program, just click on the CYCLE START button.

olf20 / Bob
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998
Re: how to hook up a e stop
« Reply #3 on: December 02, 2009, 11:57:07 PM »
Hi this is larry again thanks for the input. Yes I just whant it to pause the mach program when I push the estop button.  Also I know there will be some los of steps even a hundred steps is okay. What i will be able to do is reset the cutter at the home position and then tell the program to start from here or the next line and the machine should go to where that line is on the machine. Thenit will start the cut a few steps before it was stoped for what ever reason. I have had the machine lose 4 or 40 steps and ruin the work before I could run to the computer to stop it. It could have been save but I had no choice but to start over because I didnt know where the steps were. My board has a wire between to terminals and when it is unhooked or disconnected the board losses power. It is a  ( pc4cnc board ) What I realy need to know is if I have a pulse sent back into the computer will it tell the pause button to pause the machine . And howwould I do that  thanks for the help so far...
Re: how to hook up a e stop
« Reply #4 on: December 03, 2009, 12:10:05 AM »
hi this is larry again I didnt tell you what I was using it is a 4x8 gantry router for cutting wood. I have gecko drives and using steppers with a 8 to 1 gear reduction. I mostly am doing toys, signs, and photo typing for my own use. I use aspire 2 and bobcad.

Offline Hood

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Re: how to hook up a e stop
« Reply #5 on: December 03, 2009, 03:04:54 AM »
Ok, there are two different things here, FeedHold and E-Stop.
FeedHold will stop your machine in a controlled manner and you will not lose position.
E-Stop is for emergency use, it will stop immediately but you will lose position.

You could have either or both from external buttons but I would say a properly configured E-Stop is a must on any machine.
The way most Breakout Boards, I have seen, work is you can have an E-Stop button connected and when that contact is broken the BOB will stop putting out pulses and at the same time will inform Mach of the E-Stop condition, which will put Mach into Reset.

 I have no experience with your BOB so I am not sure if this is the case with it, I will try and have a look later in the day.
Hood
Re: how to hook up a e stop
« Reply #6 on: December 03, 2009, 09:53:39 AM »
yes when I hit the stop button on mach 3 the program does stop without loosing steps, But I had a bit come loose a couple of month ago and the bikt started to dig into the board I was cutting.  By the time I got to the mouse and stopped mach the bit was 1 1/4 inches into the board. I reset the bit and spent 2 hours reseting the program. It when 100 or so steps beyound where it was. the bit stoped moving but the machine thought it was still going. Talk about missed steps.... I only need somthing that is fast for example I could have a button in my hand so that when I push it the machine will stop dead.and also stop the mach 3 program then when I reset the mach program it woul continue. Hope you know what I mean.

Offline Hood

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Re: how to hook up a e stop
« Reply #7 on: December 03, 2009, 06:27:32 PM »
You can't do that, when you press Stop or use an external E-Stop you will lose steps if an axis is in motion unless it was moving very slowly but even then it is likely you will have lost. Maybe I should say you will lose position rather than lose steps as Mach will cut the pulses but the axis is unlikely to be able to stop dead without some motion due to momentum. 
 When you do an E-Stop you should re-home your machine so that Mach again knows where the axis actually are.

What you want to do is have a double pole E-Stop switch, use one pole to cut the power to the BOB as you have and the other pole should go to an input on the BOB and you configure that as the E-Stop in ports and pins. Then when you hit the E-Stop button, the BOB will stop putting pulses out but it will also send an E-Stop signal to Mach and it will stop instantly as well. You can then re-home your machine, back up a few lines of code and do a Run From Here.

Hood
Re: how to hook up a e stop
« Reply #8 on: December 03, 2009, 08:57:23 PM »
An E-Stop is for an emergency when things go very wrong and you need to stop it in a hurry.  It should be a big red button always within reach of the operator.  If you have to hit the E-Stop you can pretty much count on what ever is on the table to be scrap.  Just rehome, figure out what went wrong, fix it, load another blank and have another go at it. 
Re: how to hook up a e stop
« Reply #9 on: December 03, 2009, 10:23:05 PM »
Hi yes hood that is what I want to do thanks.I just wanted to go back a few steps and then home the machine to 0 X O y Oz . Then let the machine go back to where ever it was.  then start cutting from there. I like to keep things simple. Less to remember. I am not as Quick to remember thing now days as I use to a few years ago. Thanks again. The program is easy to use and easy to set up. But somtimes it is easier to just ask how to do somthing from someone who has done it or who knows. Thanks