512,476 active members
2,617 visitors online
Register for free
Login
IndustryArena Forum > CNC Electronics > Gecko Drives > hall effect limit switches working, but signal too slow to mach3
Results 1 to 16 of 16
  1. #1
    Registered
    Join Date
    Sep 2005
    Posts
    101

    hall effect limit switches working, but signal too slow to mach3

    I have had my machine for about 9 years, and just recently converted from Zylotex to a Gecko 540. So, I am re-wiring everything.
    I have scoured this forum to find out why, when my hall effect limit switches are activated it takes approx. 1.5 seconds for mach to stop the machine. This of course is far too slow, and the machine crashes. These hall effect sensors have an on board LED so I know when they become active. I am using the same switches for homing as well. (or trying to, this used to work fine with the zylotex)

    The Gecko has a 48v power supply. I have a 12v independent power supply feeding a 7805 voltage regulator to power these:
    Hall Effect Sensor Module from nicegear - New Zealand's open source and VoIP hardware specialist
    (2 per axis) with the outputs going to Gecko input 1 (x), 2 (y), 3 (z) Input 4 if for a z height setter, which works fine. Sensor is wired with 5v to the input, grounded to the same power supply as the Gecko, and the output to the inputs on the Gecko.

    They worked fine with the Zylotex board. can anyone please tell me what I am doing wrong, or show me a wiring diagram to help...
    Thanks in advance


    Ray

  2. #2

    Re: hall effect limit switches working, but signal too slow to mach3

    Hi,

    what's the method used to stop the machine once the signal triggers?

    If you use the signal to disconnect the power supply then 1.5 seconds are normal because they still have a lot of energy stored in their capacitors.
    But if Mach3 is expected to stop generating step pulses I have no clue why it could take so long.

    Christian
    My CAM Software and CNC Controller: www.estlcam.com

  3. #3
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Re: hall effect limit switches working, but signal too slow to mach3

    Ray,

    If the "Acceleration" setting in "Motor Tuning" is set to slow the steppers will over travel.

    Also if the magnetic's are to strong they may cause problems.

    Jeff...

    Quote Originally Posted by bcer960 View Post
    I have had my machine for about 9 years, and just recently converted from Zylotex to a Gecko 540. So, I am re-wiring everything.
    I have scoured this forum to find out why, when my hall effect limit switches are activated it takes approx. 1.5 seconds for mach to stop the machine. This of course is far too slow, and the machine crashes. These hall effect sensors have an on board LED so I know when they become active. I am using the same switches for homing as well. (or trying to, this used to work fine with the zylotex)

    The Gecko has a 48v power supply. I have a 12v independent power supply feeding a 7805 voltage regulator to power these:
    Hall Effect Sensor Module from nicegear - New Zealand's open source and VoIP hardware specialist
    (2 per axis) with the outputs going to Gecko input 1 (x), 2 (y), 3 (z) Input 4 if for a z height setter, which works fine. Sensor is wired with 5v to the input, grounded to the same power supply as the Gecko, and the output to the inputs on the Gecko.

    They worked fine with the Zylotex board. can anyone please tell me what I am doing wrong, or show me a wiring diagram to help...
    Thanks in advance


    Ray
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  4. #4
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    Thanks for replying. I have the acceleration for the X and Y set at 13. The Z is set slower as it was stalling when lifting.
    I do not know if this is considered "slow" or not

    Ray

  5. #5
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Re: hall effect limit switches working, but signal too slow to mach3

    Ray,

    I normally set the "Acceleration" setting to about 15% of the "Velocity" setting, IE (200 "Velocity" 30 "Acceleration") .

    If you "snap" quickly toggle back and forth between the left arrow and right arrow keys to jog, the axis will over travel if the "Acceleration" setting is to low.

    Experiment with it to see the result.

    There are no written in stone settings, they are unique to each and every machine.


    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  6. #6
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Re: hall effect limit switches working, but signal too slow to mach3

    Ray,

    I neglected to ask if you have added debounce to the machine?

    Adding debounce will induce delay in all switches, which in turn will induce over travel.

    You may have more than one variable causing the problem.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  7. #7
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    Jeff,

    Thank-you so much. Yes, it was the de-bounce. I will re-do my acceleration as well, but it was the de-bounce that was the problem.

    My wife reminded me that the PC I was using had died, and I am using a new PC since I had the limit switches working. So, when Mach got installed, the de-bounce was set. I have one last question:
    I know there is a setting in Mach to get the axis to retract once homed. I remember doing it. But I cannot find that setting. Do you know where it is? I will be doing some more research as well tonight to try to find it.
    Thanks again

    Ray

  8. #8
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Re: hall effect limit switches working, but signal too slow to mach3

    Ray,


    Homing Z is normally fully retracted (maximum Z+), your Z home switch should be almost to the top of the Z axis.

    Or are you referring to "Safe Z"?

    Jeff...




    Quote Originally Posted by bcer960 View Post
    Jeff,

    Thank-you so much. Yes, it was the de-bounce. I will re-do my acceleration as well, but it was the de-bounce that was the problem.

    My wife reminded me that the PC I was using had died, and I am using a new PC since I had the limit switches working. So, when Mach got installed, the de-bounce was set. I have one last question:
    I know there is a setting in Mach to get the axis to retract once homed. I remember doing it. But I cannot find that setting. Do you know where it is? I will be doing some more research as well tonight to try to find it.
    Thanks again

    Ray
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  9. #9
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Lightbulb

    Ray,

    Your machine may or may not require the homing for Z to be set negative.

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  10. #10
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    Jeff,

    My home switches (limit switches ) are set so that Z+, Y- and X- on the table. Leaving the tool at the front, left and highest from the table. So, having said that, here's my homing, input and diag. pages.

    Attachment 249836

    Attachment 249838

    Attachment 249840

    Let me give a little background here. After 9 years of running, I had a motor problem about 4 months ago. I decided to replace the 276oz motors with 425oz motors. The Zylotex controller wouldn't run them. So I upgraded to a Gecko 540. While I was re-building, my PC fried (which may have been the problem to start with) anyway, I was able to get my Mach profile out and re-installed it on this new (used) PC. However, with the new motors, I had to reverse some of the setting to get them to run in the correct direction. I am now running much faster, and the need for the limit switches is greater.
    What I do not understand is why this setup, when it worked before, is not working now.

    Please advise on how to get the axis to reverse off the home switches.

    Thanks again

    Ray

  11. #11
    Gold Member
    Join Date
    Feb 2007
    Posts
    4556

    Post Invert the DIR LowActive settings to change motor direction.

    Ray,


    Invert the DIR LowActive settings to change motor direction.

    Then apply the settings for the home switches like the attached image:

    Jeff...
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  12. #12
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    I will try that tonight, but I thought I did try this on the Z and the motor moved down when homing.....

    I will let you know how it goes.
    Thanks

    Ray

  13. #13
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    I went to the shop before heading out, and yes, when I switched the DIR LowActive settings all the axis moved in the wrong direction to home.

    Ray

  14. #14
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    I am still having issues with this problem. However, I have maybe isolated the problem.
    When the limit switch is triggered, the emergency stop is received by mach. However, none of the LEDs stay on in mach. Randomly the correct LED will flash, but this is very randomly, some times not at all, even though the limit switch is still active, it does not register in mach. (My limit switches have a LED on them, so I know they are working.
    So, here's my new question. What voltage does the Gecko need to activate pins 1,2,3. I am only giving them +5 volts. Pin 4 I am using for a "z" height setter, and is connected to the same power supply as the gecko (ground) it works fine.

    Thanks in advance
    Ray

  15. #15
    Registered
    Join Date
    Apr 2004
    Posts
    121

    Re: hall effect limit switches working, but signal too slow to mach3

    The G540 has opto isolators whose LED inputs have internal pull-ups to +12 volts.

    Your sensor boards and the A180 device on them are strictly 5 volt devices. When
    you tie their outputs to the G540 there is leakage current from the G540 even when
    the hall sensor is in the off state because the sensor output will not pull up much
    above 5 volts. You will need to buffer them or choose a different sensor.

    Steve Stallings
    PMDX.COM - Products for CNC and motion control applications

  16. #16
    Registered
    Join Date
    Sep 2005
    Posts
    101

    Re: hall effect limit switches working, but signal too slow to mach3

    Thanks Steve.
    I spent a bit of time on it last night, and came to same conclusion. I am going to try to match the two with a transistor tonight.

    Ray

Similar Threads

  1. hall effect home switches
    By daniellyall in forum Mach Mill
    Replies: 2
    Last Post: 10-27-2012, 02:10 AM
  2. Is anyone using hall-effect limit switches?
    By RomanLini in forum DIY CNC Router Table Machines
    Replies: 11
    Last Post: 02-28-2010, 08:53 PM
  3. Hall Effect Limit Switches
    By HimyKabibble in forum Benchtop Machines
    Replies: 2
    Last Post: 09-06-2009, 02:12 AM
  4. Hall Effect Chopper
    By legomanww in forum General CNC Machine Related Electronics
    Replies: 5
    Last Post: 12-20-2007, 09:11 AM
  5. Hall Effect Limit & Zero
    By Trebleplink in forum General CNC Machine Related Electronics
    Replies: 3
    Last Post: 10-20-2007, 12:08 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •