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  1. #1
    Join Date
    Dec 2008
    Posts
    30

    Mach 3, Soft Limits

    Hello,

    So my new problem is setting up the soft limits. I have my homing switches installed, and they work great. But what I need now is to get my soft limit switches working. What is happening at the moment, when I try and turn on my soft limits it gives me an error saying "Cannot activate when out of soft limits." But my machine is at its zero's when I get that. Has anyone had this problem? Does anyone know how to fix it?

    Thank you.

  2. #2
    Join Date
    Oct 2006
    Posts
    340
    First in Motor Home / Soft Limits configuration set The slow zone. Then Jog a distance away (this has to be at least the distance of your slow zone) from where ever you set Zero, then activate the soft limits button, In Motor Home / Soft Limits configuration I have .5 (1/2 inch if using inches) in the Slow Zone. Works for me.

  3. #3
    Join Date
    Mar 2003
    Posts
    35538
    Make sure you don't have the max and min set backwards.
    Gerry

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  4. #4
    Join Date
    Dec 2008
    Posts
    30
    Haha yeah I was doing both of those wrong. I had the max at a higher value than the min. I figured the max movement i wanted was -5, and the min to be my 0. I switched it around and it works. Ready to run a program tomorrow I think!

  5. #5
    Join Date
    Sep 2012
    Posts
    228

    Re: Mach 3, Soft Limits

    Mr Gerry,
    I would appreciate your guidance on the following. I have a conflict I can't resolve with homing and soft limits.
    For example: on my x axis I have a limit switch on X+ side, and one switch on X- that I use for homing also. In "ports and pins" - "input" , the 2 switches are on are on pin 10 (one one circuit) and my X-- , X++, and X Home are enabled and set to that pin. It all seems to work fine up to this point. In Config-Homing/Limits setting, I checked the setting for "home in the negative" and "auto zero" and 7% for the speed. I had to set my x offset at -0.6497 because the switch being both an X-- and X home is mounted that distance in the negative to obviously not be constantly triggered when X would travel to X0.000. I want to use soft limits to constraint the machine movement and now wack the switches obviously. But if I have soft limits turned on, and the X "Soft Min"is not set to bellow the home offset (-0.65) then the soft limits is triggered and a machine reset, every time it completes the homing. It seems if I don't turn off the soft limits, then I have to extend the Soft Min range beyond where the switch actually is, or this reset is triggered. This is true for all axis by the way. So for example if I want to constraint the machine soft Min to lets say x0 and the soft max to X24, then as soon as the machine moves to -0.6497 and recognizes that this is the home switch, it then immedietly responds with a reset and soft limits! Obviously if I set the Soft Min to -0.65 than the software won't stop that machine movement until it hits the switch interpreting it as a limit reached. I tried even disabling the x-- and x++ signal... Maybe you can help me understand how to set it correctly, because I have been living with this for about a year, and it just seems to contradict the whole purpose of the SOFT LIMITS function. I have a 24" x 48" table and Ideally I wanted to set the SOFT Min and Max just outside that range, and have that 1/2" of reserve travel before hitting the limit switches and hard stops. I am using your SCreenset by the way, which is awesome. Thank you in advance

  6. #6
    Join Date
    Jan 2005
    Posts
    15362

    Re: Mach 3, Soft Limits

    Frankmali17

    If I'm reading what you posted correct, you can't have the soft-limits behind the Limit/Home switches, you would have to move the Limit/Home switches to your max travel of your machine, the soft-limit will only work in front of or up to the Limit/Home switch, trying to move past the Limit Switch will trigger the Switch
    Mactec54

  7. #7
    Join Date
    Sep 2012
    Posts
    228

    Re: Mach 3, Soft Limits

    Hi Mactec,
    Maybe I need to clarify...
    My Xnegative, and X Homing are the same switch. My X Positive is a second limit switch. so the 2 switches are wired in series (normally closed) and on the same pin in the settings, this works as per design. You are correct, if the homing/limits settings are set to beyond the travel range of the machine, or the range of switches, then nothing prevents the machine from running full speed into the switches. the "Slow" setting only slow the machine in manual jogging, so that it wouldn't interfere in running G Code operations... however, if on the negative side, I don't extend the range beyond the switch, the machine goes and homes, but as soon as it moves back that tiny bit back, the reset happens, because I am "out of limits" range... seems like to avoid it you have to manually turn off the "soft Limits' and then home, and manually switch it on again.... which is a real pain. and when it causes a reset, of course power is cut of from the motors, you get a big jerk, and you can reset Mach again of course, but now how sure are you that you didn't loose accuracy? many times I find these abrupt jerks from the reset, cause a rather significant error...
    How is your machine set up?

  8. #8
    Join Date
    Jan 2005
    Posts
    15362

    Re: Mach 3, Soft Limits

    Frankmali17

    I have 2 switches ( 1 ) at each end of the max travel of each axes, one is Limit/Home the other is just a limit, anything in between can be controlled by the soft limit settings, if you don't have an expensive machine to protect, you can use just ( 1 ) switch Limit/Home per axes, & use the soft limits, it works very well when set up correct
    Mactec54

  9. #9
    Join Date
    Sep 2012
    Posts
    228

    Re: Mach 3, Soft Limits

    Yes, but does your setup work well with soft limits? do you have soft limits turned on? Or am I the only one that seems to have this conflict?

  10. #10
    Join Date
    Jan 2005
    Posts
    15362

    Re: Mach 3, Soft Limits

    Frankmali17

    My Soft limits are turned on, they work perfect, I test them to make sure they are working
    Mactec54

  11. #11

    Re: Mach 3, Soft Limits

    Mactec54 I have a similer setup i switch on each axis one at the X+ position the other at the Y+ and the other @ the Z+ which are all used for homing..... please explain how to set up the soft limits.... Do I set the soft limits a couple thousads for max on the + (plus) side (ie. .002) and to the full desired travel on the - (negative) side?
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