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### Question #: 13981

Question: 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)

Current Solution

Let me check.

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.

Respond:

### Other Possible Solutions to this Question

• 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.

• 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.

• LIMIT SWITCHES FOR AXIS. THE PRINT SHOWS THAT YOU CAN WIRE LIMITS EITHER N.O. OR N.C. SO IF THIS IS CORRECT I WOULD NEED TO TELL BOARD IN SOFTWARE HOW LOOK AT THESE LIMITS, I'M GOING GET AN INPUT LOOSE DEPEND ON IT.

BYCNC Response:
This is correct. You will need to use a method appropriate for the software you are using. Also remember that NC switches are typically wired in series, while NO switches are normally wired in parallel.

User Response:
I am using the cnc planet software for your USB board. Are the limit configurations in this software?

BYCNC Response:
Yes, Planet CNC software is compatible with the use of limit switches. Configuration information will depend on your specific application. You can view Planet CNC's information here: http://www.planet-cnc.com/files/CNCUSBController.pdf

• I am using 5 limit switches on my 3 axis machine. I am using the usb controller for planet cnc. I would like to know where all the wires related to the limit switches get connected? A diagram would be helpful.

The diagram for wiring the USB interface board is located here: https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-USB-Controller-Breakout#prettyPhoto/2/

Under the board illustration, there are three smaller diagrams of limit switch wiring. On each, there are two connections, the GND and the pin which are labeled at the ends of the circuit on the diagrams. The pin side would go to the axis label ++ or -- terminal (i.e. X++, or X--). The other end, labeled GND would connect to any ground terminal on the board.

• I purchased limit switches from you mounted them on my machine and wire them to the breakout for using pin 12 and the ground on the breakout board, after a few minutes I got a message about a limit switch trip. Am I supposed to use the extra outport on the board instead of the ground?

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.

• Can you provide recommended locations for limit switches on your kits?

Here are the recommended locations for limit switches for our CNC machine kits.

The x-axis limit switches should be located on a single gantry. This makes the wiring of the limit switches close in proximity and more manageable.
https://www.buildyourcnc.com/images/IMG_6367-800.JPG

The y-axis limit switches should be located at each end of the gantry. This keeps the switches stationary and impose minimal movement of the wire for better wire management.

One end of he gantry:
https://www.buildyourcnc.com/images/IMG_6361-800.JPG

Other end of the gantry:
https://www.buildyourcnc.com/images/IMG_6360-800.JPG

Can you provide recommended locations for limit switches on your kits?

• Limit switches for axis. The print shows that you can wire the limits either n.o. or n.c. so if this is correct I would need to tell the board in the software how to look at these limits, I'm either going to get an input or loose an input depend on how i wire it.

BYCNC Response:
This is correct. You will need to use a method appropriate for the software you are using. Also remember that NC switches are typically wired in series, while NO switches are normally wired in parallel.

User Response:
I am using the cnc planet software for your USB board. Are the limit configurations in this software?

BYCNC Response:
Yes, Planet CNC software is compatible with the use of limit switches. Configuration information will depend on your specific application. You can view Planet CNC's information here: http://www.planet-cnc.com/files/CNCUSBController.pdf

• 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?

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.

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

• I would like to make a handheld remote for the USB CNC Board using a joystick instead of momentary switches. Could you suggest one that will work with your board.

The USB interface only works with momentary switches unfortunately. If you have extensive knowledge of digital electronics, you can apply a receiver that uses a microcontroller and a transmitter with another microcontroller that produces the pulsing signal with the controls that you need.

• I have the redleaf system for my black toe machine I have wired my limit switches in series NC after setting up in mach 3 I still get limit switch tripped after apply and ok setup can only run if I disable what am I doing wrong

If you are using Mach3, the setting for the input pin 10 may be enabled as a default for use with the Emergency Stop. If there is no emergency stop on that pin, the reset will trip every time.

• In the Build your own CNC machine book, You said you use 1 1/4" angle on the main table but 1" would be better. So my question is Should I use 1" angle on the main table (4' length) and 1 1/4" angle for the BRA's and other rails?

You can use either 1" x 1" x 1/8", or 1-1/4" x 1-1/4" x 1/8" angle on the table sides. The BRAs should all be 3/4" x 3/4" x 1/8". The Y ans Z axes should use the 3/4" x 3/4" x 1/8" angles.

• I already built a 4 x 8ft carving machine, I would like to modify for laser cutting wood. Do you sell a conversion kit? I use Mach3 software and steppers. Thanks Ray

We offer a laser/spindle Z-axis attachment for our 4x8 greenBull CNC. The blackFoot 4x8 does not have a large enough gantry to accommodate the 40W laser tube.

We do sell the parts to convert your CNC milling machine to a laser, but you will need to develop the mounts that will hold all of the laser parts to the machine, if the machine was design and built by you.

We can offer guidance for this conversion.

The laser parts can be found here:
https://www.buildyourcnc.com/LaserComponents.aspx

• 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.

I will take pictures tomorrow.

Thank you. Just want to finish before the holiday.

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.

Any update?

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

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.

I will take pictures of those connections as well.

Much appreciated.

It’s my pleasure.

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

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

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.

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

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

We only have the rotary switch on one side.

• I HAVE YOUR MACH3 USB BOB, DO YOU GUYS SELL A TORCH CONTROL RELAY CAN WIRE UP TO TURN MY PLASMA ON AND OFF HOW WOULD WIFE THAT TOO THIS BOB?

We do have a relay board that words like a standard relay.

Here is the URL of the relay board that we offer:

https://www.buildyourcnc.com/item/electronicsAndMotors-breakout-Relays-relay-board-250V-12A-5V

• Would your greenBull 6X CNC machine be suitable for cutting 2024T3 aircraft aluminium? Working on a kitlpane project and I need this capability.

the greenBull can handle cutting aluminum as long as the correct bit (end mill) is used and the bit is cooled frequently to prevent chips from melting and causing damage to the bit or warping the material.

• I have nearly completed the CNC machine from the book, but I am using it with a USB breakout board, and have no idea how to wire the 6 limit switches to the board. I'm having difficulty following the diagram on the USB breakout board screen. Can someone please help me?

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.

• I have your mach3 USB BoB, do you guys sell a torch control relay I can wire up to turn my plasma torch on and off and how I would wife that too this BoB?

We do have a relay board that words like a standard relay.

Here is the URL of the relay board that we offer:

https://www.buildyourcnc.com/item/electronicsAndMotors-breakout-Relays-relay-board-250V-12A-5V

• what options can you offered to international customers to assist in them building one of your machines? International shipping of a kit would be too expensive.

We are able to ship internationally but unfortunately we cannot control the shipping costs incurred for international customers. However, if you are associated with educational programs or Makerspaces and/or Fab Labs we do offer certain discounts in some cases. Please send an email to customer service for more information on receiving a quote.

• Would you be able to provide .DWG/.DXF files instead of .NC files for the CNC Routing Machine Kit Version 1.3 please?

These files are no longer available. We suggest purchasing a kit, like the blackToe, or blackFoot as these kits are far more rigid and perform much better.

https://www.buildyourcnc.com/blackToe2x4v40.aspx

https://www.buildyourcnc.com/Item/cnc-machine-blackFoot-v4