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Author Topic: Limit switch issues  (Read 19202 times)

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Re: Limit switch issues
« Reply #50 on: December 26, 2015, 12:21:51 PM »
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And the manual says otherwise....the limit switch will stop the machine, but not stop you from pushing the wrong arrow key and causing damage to your machine....it says so right in the manual....

If you stop a car using the brakes to avoid hitting a wall, there is nothing to stop you from chosing reverse and smashing into the wall, unless your stupid.

My Mustang will do that.  ;D .. if you don't know better  ;).

Offline bfgstew

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Re: Limit switch issues
« Reply #51 on: December 26, 2015, 03:57:49 PM »
Some more food for thought - For arguments sake, your machine is all set up and homing limits work and your soft limits work. You hit Ref Home, your machine moves all axis to its home position, again for arguments sake X-0,Y-0 and Z-0, if you decide to move say the X axis past the limit switch, if it is all set up correctly, there is a limiting speed factor built into the set up that will only allow the axis to move at that speed, say 20% of normal operational speed, this will give you time to think and see that if you keep your finger on the jog button it will reach a solid stop, now at 20% speed this will not cause much, if any damage, most it will do is cause the motor to stall, but hopefully the operator will notice this and stop before this happens. Also some folks add a second limit switch after the homing switch to prevent this from happening, also the limits are normally an inch or so from the end of travel to allow for any unexpected failures, i.e. E stop can be pressed before failure occurs. Again this is all documented in the manual. You can also add limit switches on the other end of axis travel and this will give a further measure of protection over and above the soft limit set up. Again all documented.
Re: Limit switch issues
« Reply #52 on: December 26, 2015, 04:28:48 PM »
You know I don't trust the CNC, ANY cnc. So the limits on my machine are connected right in the E-Stop circuit which controls the main power contactor which quite literally stops everything, and puts Mach 3 in E-stop.  Now If I hit the limit and everything shuts down I have to push the reset button and hold it in while jogging away from the limit. My limits slide by too, not a physical stop that could break something. So you can see it move the wrong way still and not break anything. This is a pain to reset.  Or it was, once I learned my machine I stopped hitting the limits!
Re: Limit switch issues
« Reply #53 on: December 26, 2015, 06:44:05 PM »
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And the manual says otherwise....the limit switch will stop the machine, but not stop you from pushing the wrong arrow key and causing damage to your machine....it says so right in the manual....

If you stop a car using the brakes to avoid hitting a wall, there is nothing to stop you from chosing reverse and smashing into the wall, unless your stupid.

actually a more accurate analogy is buying a car with accident avoidance, setting it up so it will STOP you from hitting a wall, then overriding the accident avoidance system and purposely smashing into the wall....

But seriously, why would someone want to by pass the limit switch that they installed and set up, to purposely damage their machine?
Re: Limit switch issues
« Reply #54 on: December 26, 2015, 06:49:22 PM »
Some more food for thought - For arguments sake, your machine is all set up and homing limits work and your soft limits work. You hit Ref Home, your machine moves all axis to its home position, again for arguments sake X-0,Y-0 and Z-0, if you decide to move say the X axis past the limit switch, if it is all set up correctly, there is a limiting speed factor built into the set up that will only allow the axis to move at that speed, say 20% of normal operational speed, this will give you time to think and see that if you keep your finger on the jog button it will reach a solid stop, now at 20% speed this will not cause much, if any damage, most it will do is cause the motor to stall, but hopefully the operator will notice this and stop before this happens. Also some folks add a second limit switch after the homing switch to prevent this from happening, also the limits are normally an inch or so from the end of travel to allow for any unexpected failures, i.e. E stop can be pressed before failure occurs. Again this is all documented in the manual. You can also add limit switches on the other end of axis travel and this will give a further measure of protection over and above the soft limit set up. Again all documented.

that's awesome...but can you at least admit that maybe the manual written in 2003 might not be so cut and dried to everyone as it is to you? I mean, don't you think it's a little errr "silly" to refer to this documentation, go to the section on limit switches, and find yourself reading the HISTORY of parallel ports? Then as you're reading on how to set your limit switches, oopsy, it doesn't say how, it says "go to yet another section on setting up mach 3"....so, why I am in the section on setting up limit switches if I have to go to another section to find out how to set up limit switches?
Re: Limit switch issues
« Reply #55 on: December 26, 2015, 07:01:05 PM »
Ok, this is my xml file
Re: Limit switch issues
« Reply #56 on: December 26, 2015, 07:02:39 PM »
and this is for the troll who said he doesn't believe I know anything about operating a cnc.....

Offline bfgstew

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Re: Limit switch issues
« Reply #57 on: December 26, 2015, 07:34:50 PM »
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But seriously, why would someone want to by pass the limit switch that they installed and set up, to purposely damage their machine?

You are missing the point, the point is that you can if you want to, maybe for maintenance purposes, maybe you have a job that is that bit to big to fit on the machine and you need that extra inch. If you want to bypass it and run the head off the x axis then go ahead but don't come complaining to anyone. Please get this into your head, Mach3 works and works well when it is set up correctly, and that means reading and understanding the manual provided.Ok, maybe, just maybe the manual can be a little confusing but, and this is the BIG but, if you are unable to understand that Mach3 is a software that THE USER has to set up to their own needs and not just work soon as you plug it in, the sooner we can get your issue sorted. It is what it is, it works for thousands of people and they are very happy with it, it does what it says on the tin, nothing more, nothing less and for $175 or so I feel it is excellent value for money.

Right moving on, firstly -

You need to identify the limit switches on your machine, check how they are wired up, how they are connected to the drivers/BOB/controller. Unfortunately I cannot access your XML file as I am at work at the moment, but someone will investigate it for you. We can then start to get this minor problem sorted instead of going around and around in circles. Let's move forward please.
Re: Limit switch issues
« Reply #58 on: December 26, 2015, 07:42:50 PM »
I think I may have found one of the issues: the switches aren't turned on as limit switches as well as homing switches.....now why it tries to bypass the switches? I dunno....that will take further investigation....

I tell you one thing: I copied my entire mach3 folder onto my design computer and after updating I've noticed something that wasn't in the ports and pins window before: automatic setup of inputs....

Offline bfgstew

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Re: Limit switch issues
« Reply #59 on: December 26, 2015, 07:47:39 PM »
Its a start