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?

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.

Yes, the 651 oz/in motor requires a driver that is compatible to the motors (the motor will draw 6 amps max and the driver paired with this motor will be able to allow for a 6 amp draw). I would also recommend a 36 volt power supply for better high velocity performance.

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I HAVE ONE OF YOUR SMALLER STEPPER MOTORS RUNNING MY X AXIS BRIDGE CRANE AND IF IT IS MOVED TO FAST THE MOTOR SOUNDS LIKE SKIPPING STEPS WILL 651OZ REQUIRE A DIFFERENT POWER SUPPLY CONTROLER?

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 NENA 14 motor is paired with this driver and will work very well: https://buildyourcnc.com/item/motion%20electronics-steppermotordriver-newbiehack-Motor_Drivers-2!5_Amp_modular

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I cannot find a driver for the NEMA 14 Stepping Motor (17 oz-in 1/4" dual shaft) on your site, would something like the Pololu DRV8834 be okay? (I note that the stepper requires 2.7v)

Yes, the 651 oz/in motor requires a driver that is compatible to the motors (the motor will draw 6 amps max and the driver paired with this motor will be able to allow for a 6 amp draw). I would also recommend a 36 volt power supply for better high velocity performance.

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I have one of your smaller stepper motors running my X AXIS bridge crane and if it is moved to fast the stepper motor sounds like it is skipping steps will the 651oz stepper motor require a different power supply and controler?

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

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 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?

The 2.5 amp driver can only accept a power supply between 12 volts and 24 volts. If a 36 volt power supply is used for this driver, the main driver chip will exceed its maximum voltage rating and cause failure.

If you need to spin your motor faster, you can either use a more appropriate driver (i.e. 3.0 amp driver) or you can change the mechanical parts so the axis has faster travel.

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Can I connect a 36V power supply to 2.5 AMP Stepper Motor Driver. On the actual driver it shows 12V - 24V, but in the description and data sheet it indicates that it can accept 8V - 45V. Will I benefit from more powerful power supply. Thanks

Our 1.5/2.2kW spindle will work with both setups, in our wiring diagram it is more seen as the Euro/AUS-style, however you can do the same thing with the North American style as well. Also depending on if you have single or three phase 220V, you can use pins R, S, T. A manual will arrive in the VFD box, which will have further information and diagrams.

Please seek a certified electrician if you are unsure of any aspect in wiring the spindle or VFD, since wiring to main lines will require wiring of the plug and main lines to the inverter and to avoid any damage or injury's while installing the 1.5/2.2kW spindle and VFD combo.

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On the wiring diagrams for the 220v inverters I noticed that there is one hot (220) a neutral and a ground. Will the inverter work with the American split phase system? Hot (120) hot (120) ground?

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?

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

We could not guarantee, nor say, whether or not your current software would be able to utilize the USB breakout board. Our USB breakout board is designed for use with Planet CNC software found here, http://www.planet-cnc.com/index.php?page=software

As far as we know, this is the only CNC Controller software that operates on a USB breakout controller.

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Is it possible to manage USB Controller (Breakout) from my own (custom) Windows application? Is there a driver API or smth for that?

If your motors are hot to the touch, this is normal. Current is being drawn by the motor coils as the motor moves and as the motor stays at a position. If the motor is not using the current in the coils to move (holding it's position), the energy will be translated as heat (rather than motion, sound or light). Even while moving, some of the energy will be lost as heat. Remember that energy cannot be created nor destroyed.

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Are the stepper motors on x and y axis suppose to be hot after running for approximately 30 min. I can touch them but they are hot.

You can find the datasheets to our motors be going to the the stepping motor category page https://www.buildyourcnc.com/category/nema and selecting the motor. This will bring you to the product page for the motor and all of the motor information will be found there.

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I would like to design my own CNC router around one of your electronics bundles, either the 3 Axis - Heavy Gantry or 3 Axis - All Large Motors. Do you have the data sheets for the motors so that I can use the dimensions in my model?

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?

That driver (not purchased here) is a standard 3.0 amp driver that will have the dip switch settings on the top of the driver. You will need to determine the amp rating of you motor for the scheme that you wire your motor to the driver (bipolar parallel is recommended in most circumstances but can depend on your power supply output). Check the stepping motor datasheet for your motor to determine this amp rating.

The other set of switches will be configure the microstepping. This will depend on your mechanical setup (i.e. lead screw, rack and pinion, roller chain, timing belt, etc.) and the specifications of such mechanical parts.

This general formula (which can be searched using the Customer Service Live with many examples): step/inch = (natural motor steps * desired microsteps) / (mechanical travel for one motor rotation)

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I bought a, 3-Axis NEMA23 CNC Kit (36V/9.7A/382oz-in/KL-4030.but dont know how to set the dip switches on my drivers. The place I bout the kit from isent very good and support.

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.