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.

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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?

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

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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.

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.

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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.

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.

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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?

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.

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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?

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.

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I will take pictures tomorrow.

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Thank you. Just want to finish before the holiday.

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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.

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Any update?

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

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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.

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I will take pictures of those connections as well.

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Much appreciated.

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It’s my pleasure.

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

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

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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.

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


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

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We only have the rotary switch on one side.

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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.

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

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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?

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.

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

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.

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

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

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

All of our CNC machines can carve at that depth without a problem and do 3d carving. Our typical application is cutting sheet materials, but a good percentage of our customers cut 3D bas reliefs or even more complex 3D objects using reference points and jigs.

Most of our CNC machines have a Z travel of at least 6 inches for the smaller machines and 7 to 10 inches for our larger machines. The Fabricator Pro has a Z travel of 10 inches.

Depending on your application, you will need to consider the length of the end mill (more than the deepest depth of the 3D carving) and the stock that you will be using. If the stock plus the length of the end mill exceed the clearance with the Z axis raised to the top extent, then you will need to consider the way the table/bed of the machine is formed (maybe with a depression to take advantage of the greater need for clearance).

The greenBull has the capability of Z axis travel of up to 36 inches, but I would recommend, if milling wood, that the Z-axis not extend more than 12 inches to reduce deflection.

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Most of the CAM software on the market will have 3D profile machining operation capabilities. CAMBAM has a very nice 3D prpfiling feature. The Vectric line of software can definitely handle this as well.

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All of the pics and videos show your cncs cutting sheet materials, I'm interested in carving 3d images in plastic and hardwood slabs up to 2" thick. What machine and software would you recommend?

Consider the loads on each axis when choosing appropriate stepper motors. If your holding torque is maxed out at roughly 16oz/in (1lb/in), then you could use the NEMA 11 or 14. Also consider the shaft sizes and current ratings when choosing drivers that pair with the motors.

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I am planning to build a scratch CNC machine to do rotary engraving on writing pens. Can you recommend the parts I would need? I'm thinking NEMA 14 (11?) and 3/8" acme rod. Not sure which linear motion to use. I have an old lathe to use for the 4th axis.

No, you should not have received two parallel breakout boards in your CNC kit. You can return the extra item using standard shipping with COD. Our apologies for the confusion and the inconvenience.

I will answer the other question as another FAQ. Please check the Customer Service page to see the answer to that question.

If you have difficulty finding the answer, here is a link:
https://www.buildyourcnc.com/FAQ/13636

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I HAVE A 2000 WK 11–3 Z LIMIT SWITCHES GOING TO C10R10 BREAKOUT BOARD . CAN ALSO USE THEM AS MY HOME POSITION WELL. NEED THE WIRING CONFIGURATION

Are you trying to determine how to wire the switches or where to place them on the Vertical Laser XL? Let me know and I will provide some pictures or video on how to do this.

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Kind of both. Have somewhat of an idea as to how to wire them but you included rotary and other limit switches. Not sure which ones to put where. Never worked with these before.

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Do you have a more detailed diagram of the rotary and 15A limit switches on the vlxl?

Make sure to wire the limit as normally open.

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[575] I had limit switches working and on input 2. Now looking at Mach 3 diagnostics, Input 2 is continuously on and triggers limit stop. I removed all input 2 so the machine can run. Rebooted all. Anyway to reset Input on card?

No, you should not have received two parallel breakout boards in your CNC kit. You can return the extra item using standard shipping with COD. Our apologies for the confusion and the inconvenience.

I will answer the other question as another FAQ. Please check the Customer Service page to see the answer to that question.

If you have difficulty finding the answer, here is a link:
https://www.buildyourcnc.com/FAQ/13636

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I have a 2000 WK 11–3 Z limit switches going to A c10r10 breakout board . Can I also use them as my home position as well. I need The wiring configuration

The USB Interface page: https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-USB-Controller-Breakout

On this page, there is a datasheet that explains the connection schemes for the limit switches on step 1 of the instructions. The datasheet explains single and multiple switch configurations and parallel/serial connections schemes for the NO/NC (Normally Open/Normally Closed states).

If there is further information you need, please reply on this FAQ.

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Please provide detailed instructions on how to connect limit switches to CNC USB BOARD. I can not find instructions anywhere. I am new to cnc world and really need help. Thanks

All of our CNC machines can cut melamine. If your application (kitchen doors) requires large cutting area, then I would recommend the following machines:

- greenBull 4x (4'x8'), 5x (5'x10') or 6x (6'x 12')

- greenLean 4'x8' vertically oriented CNC machine

- Or our Fabricator Pro 4'x8' metal CNC machine

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CAN YOU RECOMMEND WHICH CNC MACHINE TO GO WITH FOR CUTTING MELAMINE AND MAKING KITCHEN DOORS FROM MDF. ALSO DO PROVIDE TRAINING ON OPERATING SETTING UP SHOP PRODUCTION USE? THANKS

We have a tutorial on setting up limit switches here(

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Diagnostics(Alt7) page-LED (4th from left on top row) is on. Having trouble configuring Limit & Home Switches. I think this LED is for pin 15. Any ideas where to look to diagnose?

When the z axis is going down, the laser turns on. When the z axis is going up, it turns off. The z axis directions is only a signal that is either 5v or 0v. That determines the direction. In vectric, you will need to set your machining operations with a very very small depth so the time it takes to get to its final depth is a very short time.

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AM NOT SURE HOW TO SET THE Z AXIS TURN ON/OFF LASER WHEN CREATE CODE. KNOW THAT ITS TYPICALLY Z-AXIS MOVEMENT DOES THIS - BUT YOU DONT SHOW ANYTHING HOOKED UP IN PLACE OF AXIS.