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Newbie needs HELP with limit switches
« on: January 25, 2009, 12:37:15 PM »
First of all Hello to all from this frustrated newbie to cnc.  I have read almost all the posts here relating to limit and home switches.  I have read the Mach3 manual and watched the videos numerous times but  I still cannot find what I am doing wrong.

Before going into my problem let me tell you what I have and what have been able to do.  I purchased an
X-2 from SyilAmerica. I had no problems setting the machine up  and  checking out motor operations and movement on all three axes.  I even managed to create simple drawing, convert it to g code and run it on the machine.  Instead of a tool in the spindle I used a short pencil in its place to avoid damage to my machine.  Everything worked perfectly.

My problem started when I tried to test the limit switches and set soft limits.  My machine just blows right by all the individual limit switches as if they were not there.  Same with the soft limits.  I know I am missing something that is probably very simple but for the life of me I can’t figure it out.  Can anyone help me?

Thanks from Ken J

Offline Hood

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Re: Newbie needs HELP with limit switches
« Reply #1 on: January 25, 2009, 01:12:42 PM »
Attach your xml and give us an idea how the limits are wired, their positions and type of switches.
Hood

Offline jimpinder

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Re: Newbie needs HELP with limit switches
« Reply #2 on: January 26, 2009, 05:18:46 AM »
There is a bit of a learning curve with limit and home switches. Post Hood your XML, and he will look at it. In the meantime I will try and explain the problems.

You do not say whether you bought the Syil  electronics with the machine, but I will assume you have.  As far as I see it the machine is, to a great extent, prewired, and shows the limit/home switches as 15,13,12 and 11 (x,y,z and a). What it does not say is whether that signal is +5v or 0v.

Go to Config/Ports and Pins/Inputs and  configure the "Home" switches of x,y and z to the pins shown - port 1, pin ** and enable them. Now come out of that, and change to the dianostics page and see what that says. The diagnostics page shows leds for all the switches. Are any of them activated - Yes or No. If the answer is No, then manually press the switches, or activate them and see if the led lights - if they do then all is well.

If they are already on, then you have them incorrectky configured. Go back to Ports and Pins, Inputs, and tick the "Active Low" box for each pin. Look on the diagnostics page, and this should extinguish the led's, and they should now light when activated.

If that is alright, then you are away, and your home switches will work.
Mach 3 knows when it is "homing", or is "limiting" and therefore you can use the same switches for both functions. If the switches are obviously placed for a limit function at one end (or the other) of an axis, then you can activate the appropriate "limit" on the Ports and Pins/Inputs page, ascribing the same pin number as you did for the home function. It does not say if there are switches at both ends of the axis, if there are, you can ascribe both limits. Don't worry about use, Mach 3 will pick out which function it needs.

Your problems will begin if your leds are not lighting at all, then we will have to start seeing why.
Try this first, and come back if you have problems.





Not me driving the engine - I'm better looking.
Re: Newbie needs HELP with limit switches
« Reply #3 on: January 27, 2009, 05:38:38 PM »
Hood:

Attached is my .xml file. At least I hope its attached.  I do have the soft limits working but the mechanical limit switches are still dead.  Perhaps I don't have the right swiches set in Mach3.  I have no idea how to do this if that is what is needed.  When soft limits are "on" I can manually push a switch and get an on led on the diagnostic page but the machine keeps on going.

Thanks for your help.

Ken J

Offline Hood

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Re: Newbie needs HELP with limit switches
« Reply #4 on: January 27, 2009, 05:43:27 PM »
you dont have your limit switches enabled in Ports and Pins. If you are using the same switches for limits and home switches then you just use the same port and pin numbers, eg x+ and x- would be Port 1 Pin 10 as that is what your x home switch is on.

Hood
Re: Newbie needs HELP with limit switches
« Reply #5 on: January 31, 2009, 05:48:36 PM »
Thanks to both jimpender and Hood for your help.  Your information was a big help.  Based on your help I did get my switches working properly.  Unfortunately I did something that has stopped from setting soft limits.  I keep getting the error message "Machine out of limits for soft limit activation".  No matter what I do I can't get the soft limits to work.  Do either of you have any idea what I might have done or how I can fix this problem?  Many thanks in advance.

Ken J

Offline Hood

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Re: Newbie needs HELP with limit switches
« Reply #6 on: January 31, 2009, 06:03:32 PM »
You must have the settings wrong for the softlimits. Where are your limit switches  and home switches in relation to table movement and what do you have the softlimits set to?
Hood
Re: Newbie needs HELP with limit switches
« Reply #7 on: January 31, 2009, 07:11:14 PM »
Hood,

x swirch is at the left end of the table, y is close to the column and y is at the top of the column. All minimum limits set to zero and max set to x=8, y=3 and z= - 4.  Thanks. Ken J

Offline Hood

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Re: Newbie needs HELP with limit switches
« Reply #8 on: January 31, 2009, 07:20:33 PM »
You Z min should be -4 and  Z max 0, thats probably where you are getting the problem but if not then just confirm that when homed your table is fully to the right , fully towards the column and fully Up in Z.

Hood