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Question #: 9020

Question: how to wire limit switches

Current Solution

The parallel breakout board allows for 4 input connections. Each input connection can have an unlimited number of switches, but if you need to separate the switch circuit for, say, all of the home switches, you can use another input pin. There is no need to add another breakout board to add more switches unless you need to use the input pins for totally unique conditions that may or may not be related to CNC functions.

Customer response:
To Clarify: I need to set up 3 home switches which can double for limits (that's 3 pins.). Another pin for a probe. That's 4 pins used. Now I need to set up the other limit and E-stop switches. No pins left, how do I do that? Can a ground pin be doubled up on?

Plus, I have a SuperPID. Another pin?

Additional answer:
You can put all of your limit switches (including the E-stop which serves the same purpose as the limit switches) and home switches on a single pin. When homing, mach3 will move the axis it wants to home, hit the switch, pull away from the switch, then move the next axis and repeat the steps for the next two axes.

The probe is on the 2nd pin. The SuperPID is on the 3rd pin and now you have another pin remaining.

The GND terminal can be doubled up.

Additional Information:
how about a diagram to reference showing the pin-out to use

Here is the diagram for the parallel breakout board (pins 10 through 13 are used for input):

The circuit is from the GND to the input

Here is the diagram for the Mach3 USB board (pins I1 through I4 are used for input):
https://www.buildyourcnc.com/Documents/Electric%20Wiring%20Diagram.pdf
The circuit is from the V- to the input pin

Respond:

Other Possible Solutions to this Question

  • How are limit switches connected to the AWC708 controller?

    If you are using the AWC708 or equivalent laser controller, the limit switches will connect between the EL input terminal and the GND terminal in normally open (NO) connection. Most limit switches can be connected as NO, or normally closed (NC).

    For instance, a limit switch for the X- limit will be connected from the ELX- terminal to the NO connection of the limit switch, then a connection from the GND terminal on the laser controller to the COM connection to the same limit switch.

    Click the link to respond:
    How are limit switches connected to the AWC708 controller?

  • How should I connect the limit switches to my laser controller?

    If you are using the AWC708 or equivalent laser controller, the limit switches will connect between the EL input terminal and the GND terminal in normally open (NO) connection. Most limit switches can be connected as NO, or normally closed (NC).

    For instance, a limit switch for the X- limit will be connected from the ELX- terminal to the NO connection of the limit switch, then a connection from the GND terminal on the laser controller to the COM connection to the same limit switch.

    Click the link to respond:
    How should I connect the limit switches to my laser controller?

  • How many feet of wire would you typically use to wire 6 limit switches on a 5x machine? (using your suggested location for said switches)

    Let me check.

    Additional Information:
    We suggest wiring the X and Y axes. We haven't seen the need for wiring the Z axis, but that is totally up to the CNC user as their application may require this use.

    I measured 13 feet of cable for the X and Y limit switch connections on the greenBull 5X gantry (2 limit switches on one gantry side for X limits and 2 limit switches on the gantry front extremes for Y axis limits). You will need to estimate how much more cable you will need from the gantry to the control box that you are using. I generally estimate the extra to be measured from the end of travel on the x-axis to the middle of the x-axis travel and then where you would position the control box from there.

    Click the link to respond:
    How many feet of wire would you typically use to wire 6 limit switches on a 5x machine? (using your suggested location for said switches)

  • Limit, E-stop and home switches: To set up the maximum number of switches set up I would need 2 BOB's, correct? How is this implimented and wired?

    The parallel breakout board allows for 4 input connections. Each input connection can have an unlimited number of switches, but if you need to separate the switch circuit for, say, all of the home switches, you can use another input pin. There is no need to add another breakout board to add more switches unless you need to use the input pins for totally unique conditions that may or may not be related to CNC functions.

    Customer response:
    To Clarify: I need to set up 3 home switches which can double for limits (that's 3 pins.). Another pin for a probe. That's 4 pins used. Now I need to set up the other limit and E-stop switches. No pins left, how do I do that? Can a ground pin be doubled up on?

    Plus, I have a SuperPID. Another pin?

    Additional answer:
    You can put all of your limit switches (including the E-stop which serves the same purpose as the limit switches) and home switches on a single pin. When homing, mach3 will move the axis it wants to home, hit the switch, pull away from the switch, then move the next axis and repeat the steps for the next two axes.

    The probe is on the 2nd pin. The SuperPID is on the 3rd pin and now you have another pin remaining.

    The GND terminal can be doubled up.

    Additional Information:
    how about a diagram to reference showing the pin-out to use

    Here is the diagram for the parallel breakout board (pins 10 through 13 are used for input):

    The circuit is from the GND to the input

    Here is the diagram for the Mach3 USB board (pins I1 through I4 are used for input):
    https://www.buildyourcnc.com/Documents/Electric%20Wiring%20Diagram.pdf
    The circuit is from the V- to the input pin

    Click the link to respond:
    Limit, E-stop and home switches: To set up the maximum number of switches set up I would need 2 BOB's, correct? How is this implimented and wired?

  • How do I wire the limit switches on the VLXL? Also, where do I place them? You included 2 rotary and two other limit switches.

    You can actually select many places for the switches, depending on where you think your zero will be. I will take pictures of where we positioned our switches. We set the positions so the zero is at the bottom left corner of the machine.

    Additional Information:
    I will take pictures tomorrow.

    Additional Information:
    Thank you. Just want to finish before the holiday.

    Additional Information:
    Not a problem at all and my apologies for not having that information. I have been meaning to put up a video on the limit switch connection as it is somewhat difficult to explain the process in words and diagrams.

    Additional Information:
    Any update?

    Additional Information:
    I plan on driving to the office later today and take pictures.

    Additional Information:
    Thank you. I've just done almost everything else. Just waiting for the grade 3 grease in the mail. Also, where do you suggest connecting the cable carriers? I ran everything through the top but the carrier is getting kind of full. Because of that, it is pushing the belt out when the gantry moves.

    Additional Information:
    I will take pictures of those connections as well.

    Additional Information:
    Much appreciated.

    Additional Information:
    It’s my pleasure.

    Additional Information:
    I’m almost to the office. I’ve been shuttling my kids around today. Sorry for the wait.

    Additional Information:
    I’m adding the images to the end of the VLXL instructions.

    Additional Information:
    The limit switch connections use the NO (Normally Open) terminals. That means that the switch, when not engaged, is normally open (no connection between the com and the NO terminal). When the switch is engaged, then the connection is closed and the NO and COM terminal become connected, making a circuit.

    Additional Information:
    Did you bend the arm on the x switch? Or can you mount it flush with enough give to trigger? Same on both sides?


    Additional Information:
    It does look like it is bent in the picture. No, you do not need to bend the arm of the rotary switch.

    Additional Information:
    We only have the rotary switch on one side.

    Click the link to respond:
    How do I wire the limit switches on the VLXL? Also, where do I place them? You included 2 rotary and two other limit switches.

  • Can you tell me what gauge wire is needed for limits switches and the spindle?

    The hookup wires you will need is 22 to 24 AWG stranded and shielded for the wiring of the limit switches and E_Stop. Our kit customers select various places for these switches, so we don't supply the wiring. If you don't use shielded cable, you will need to change the debounce setting in Mach3 (if that is the control program you are using).

    We typically use 14 AWG stranded wire for the VFD to Spindle (U, V, W) connections.

    Click the link to respond:
    Can you tell me what gauge wire is needed for limits switches and the spindle?

  • Limit switches connect to AWC708c laser controller

    If you are using the AWC708 or equivalent laser controller, the limit switches will connect between the EL input terminal and the GND terminal in normally open (NO) connection. Most limit switches can be connected as NO, or normally closed (NC).

    For instance, a limit switch for the X- limit will be connected from the ELX- terminal to the NO connection of the limit switch, then a connection from the GND terminal on the laser controller to the COM connection to the same limit switch.

    Click the link to respond:
    Limit switches connect to AWC708c laser controller

  • How long are the wires on the proximity switches you over

    The NPN proximity switches we stock have 43" (1.09 meters) of cable and the PNP proximity switches we carry have 48" (1.21 meters) of cable.

    Click the link to respond:
    How long are the wires on the proximity switches you over

  • wiring limit switches in series NC to the V5 Break Out Board

    When wiring limit switches to the breakout board, generally NC (Normally Closed) are connected in series (acts like a wire that when broken, breaks the circuit). NO (Normally Open) is generally wired in parallel where if one is pressed, the wire creates a circuit connecting the pin to gnd.

    Additional Information:


    Additional Information:


    Additional Information:

    Click the link to respond:
    wiring limit switches in series NC to the V5 Break Out Board

  • How can I convert from Xylotex to yours, four axis with limit switches. Have parallel PC and steppers on machine.

    Sure, the USB interface has a place for 4 axes of limit switches.

    Each axis can have two limit switches: one for the ++ (positive) end and one for the -- (negative) end. The positive end would be the limit switch at the end of the machine that, say the machine has a 4'x8' area, reaches a bit after the 8 foot mark. The negative end would be the limit switch behind the 0 foot location behind the origin. If the origin is in the middle, the negative would be at a little more than the -4 foot end and the positive would be at a bit more than the +4 foot end. Note that you can have more than one switch on each pin where the NC is connected in serial fashion and the NO is connected in parallel fashion (this can be seen on the diagram in the multiple limits switch section). The software configurations for the limits switches are under File -> Settings -> Limit.

    A typical limit switch has three connections on it. These connections consist of COM (common), NC (normally closed) and NO (normally open). The COM would generally go to GND and the NC or the NO would go to the pin. If the NC is used, then the the switch is constantly connected until the switch is pushed (engaged) then the connection from the pin to gnd is broken (open). Use the settings in software to set whether in NC or NO configuration.

    Let me know if this information was helpful (or not) by adding information to this question. Thanks.

    User response:
    Thank you very much for this helpful information. I'm still a little fuzzy on how the 6 limit switches physically connect to each other and to the USB breakout board. You've stated one switch (home) goes to positive and another switch (limit) goes to negative. Are all the GND prongs from all 6 switches connected to each other and going to GND on the breakout board, or no? And the NC prongs, how exactly are they connected to each other? And to the board? There has to be a diagram somewhere shows this visually, no? I don't know how to wire the switches in series or in parallel. I have already physically installed all the switches on the machine and ran the wires to where the board is. Now I just need to know where to plug these wires into the board. Also, taking into consideration that I'm using the Planet CNC software, the only settings I have pertaining to limit switches is "Enable/Disable" for each axis, and the actual limit for each axis. Nothing about NC or NO. Is that only in Mach3?
    Thank you.

    buildyourcnc response:
    On the USB interface, the COM on the switch connects to GND and the NC or NO connects to the input pin (i.e. x++, y--, etc.)

    Limit switch configuration is rather difficult to understand, especially with series and parallel. You can think of series as a single wire going from GND to the axis letter input terminal (i.e. X++ or X--). If the wire is broken, then the circuit is open (or the switch is engaged in a normally closed scenario). Normally closed is like an actual wire, and when engaged, the switch "opens" (breaks the wire). This is why we recommend in some systems that you can put many switches in series on a single pin. When one of the switches is engaged (breaking the connection) then the entire circuit of switches is broken and the machine stops.

    In a parallel scenario, the state of the circuit is always broken until the one of the switches is engaged and the circuit is then closed or connected. The topology looks like a ladder. All the switches connect to both sides of the ladder and the switches are like the runs of the ladder (the horizontal bars that the feet are placed while climbing). Imagine all of the switches broken in this scenario (normally open). It would be like the ladder could be split in two, but if one of the ladder runs (switches) is closed by engaging it, then that run would connect both sides of the ladder and the two sides of the ladder would have a connection.

    There is a diagram on the USB page of the various limit switch configurations. If you need more information (visual and/or otherwise), please let us know and we will immediately add that information to benefit everyone.

    Click the link to respond:
    How can I convert from Xylotex to yours, four axis with limit switches. Have parallel PC and steppers on machine.

  • PROBLEM WITH LIMIT SWITCHES TRIGGERING

    Are you using shielded wire? If so, take the shield to ground. If there are any other wires in the cable that is not being used, ground those as well. The customer can also try moving the cables as far away as possible from the motor wires and motors.

    Additional Information:

    Click the link to respond:
    PROBLEM WITH LIMIT SWITCHES TRIGGERING

  • Are there any videos detailing wiring of limit switches and stop button?

    This video may serve helpful on the homing and limit switches:
    https://www.buildyourcnc.com/PrimeronHomingandLimitSwitches.aspx

    I don't go into great detail on the wiring, however. If after you watch that video and you still need a video, please let me know and I will make a video on the wiring of limit switches and the E-stop button.

    Click the link to respond:
    Are there any videos detailing wiring of limit switches and stop button?

  • limit switches tripping from interferencee

    http://buildyourcnc.com/PrimeronHomingandLimitSwitches.aspx
    There is a pin setting in Mach3 that says how to react to the inputs from the switches. Your setting is probably wrong as the trigger happens immediately.

    You may want to think about shielded wire and/or a resistor on each limit switch line. If there are stray wires, connect them to ground. Additionally, the shield from the shielded cable insulation should alse connected to ground at both ends.
    Try upping the Debounce interval in Mach3. You have to adjust the debounce interval. You go to config,general config, and it is in the top right corner. I set mine to 100 and it seems to work well.

    Additional Information:
    how to solution cnc revo 540 limit tripped error?


    Additional Information:


    Additional Information:

    Click the link to respond:
    limit switches tripping from interferencee

  • MY LIMIT SWITCHES ARE TRIGGERING AT RANDOM.

    Are you using shielded wire? If so, take the shield to ground. If there are any other wires in the cable that is not being used, ground those as well. The customer can also try moving the cables as far away as possible from the motor wires and motors.

    Additional Information:

    Click the link to respond:
    MY LIMIT SWITCHES ARE TRIGGERING AT RANDOM.

  • The limit switches keep triggering or erroring.

    Are you using shielded wire? If so, take the shield to ground. If there are any other wires in the cable that is not being used, ground those as well. The customer can also try moving the cables as far away as possible from the motor wires and motors.

    Additional Information:

    Click the link to respond:
    The limit switches keep triggering or erroring.

  • The limit switches keep triggering or erroring.

    Your limit switch circuit is receiving too much interference from nearby equipment (stepping motors for example). Make sure to use shielded cable and the shielding, and any other wires or conductive material must be grounded. The limit switch circuit cables and wires must be as far as possible from motor wires.

    If all else fails, just use soft limits until a solution to the limit switch circuit can be determined.

    Click the link to respond:
    The limit switches keep triggering or erroring.

  • Do you have a wiring diagram for a 3 axis system using your compotents. It would be nice if it showed the estop, limit switches,relays...

    Depending on the Breakout board that was purchased with your electronics combo, either USB or Parallel:
    USB: https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-USB-Controller-Breakout#prettyPhoto/2/
    Parallel: https://buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay#prettyPhoto/2/

    These will have the inputs labeled on the board itself, for example:
    USB will have the inputs for all the axis from X, Y, Z, A, limit switches.
    Parallel there will be 4 inputs 10, 11, 12, 13, 16(relay). Which can be used as E-stop, Limits (for all axes if wired in a closed loop), and one relay for a spindle control on/off via mach 3 or mach 4 or a specific relay control that you desire.

    Click the link to respond:
    Do you have a wiring diagram for a 3 axis system using your compotents. It would be nice if it showed the estop, limit switches,relays...

  • Do you sell 22 to 24 AWG stranded and shielded for wiring of the limit switches and E_Stop?

    The wire that we sell for the limit switch wiring is here: https://www.buildyourcnc.com/item/3d-printer-component-cnc-electronicsandmotors-cable-wire-3-conductor-22-awg-wrcon-cablewire3conductor22awg

    This is shielded cable to make sure there isn't any external interference with sensitive components and long wires associated with limit switches. This is necessary due to the interference caused by the motors on a CNC router and the milling process.

    Additional Information:
    So unshielded is cool. That's what I was curious about. Cheers.

    Additional Information:
    Absolutely. It's really the only type of cable I would recommend for connecting limit switches.

    Click the link to respond:
    Do you sell 22 to 24 AWG stranded and shielded for wiring of the limit switches and E_Stop?

  • DO NEED LIMIT SWITCHES, IF SO WHAT IS YOUR RECOMMENDATION?

    Limit switches are not really needed for this level of a machine, but if you do want to use them, then you will need to connect them with shielded cable and ground the shield at both ends and any other non-used wire in the cable. Limit switches are very susceptible to the motor interference. You will also need to adjust the debounce in the software you will use.

    Click the link to respond:
    DO NEED LIMIT SWITCHES, IF SO WHAT IS YOUR RECOMMENDATION?

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