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?

Attaching two motors in parallel is possible, but you will need another motor and driver for the opposite side. Each motor must have its own driver to work accordingly and fluently. The two can be wired together, to the same pins on your breakout board and set the dip switches on the driver to match the ones on your x-axis(ex). But remember to view the orientation of the motor and which way it spins, since it is on the opposite side it will have to be orientated correctly to move in sync with the other motor.

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I just finished building my first CNC with the electronics I purchased from you and I am already thinking about improving it. I would like to build a 2 motor X axis solution. Is it possible to attach 2 parallel motors and drivers to the BlueBrew Breakout Board? If so, how?

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.

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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

For safety's sake I would recommend a new board because they are inexpensive compared to the electronics that they support. Alternatively, it's possible that the one dead pin is a simple fix, such as a bad connection or solder joint; if you feel comfortable making those repairs then it could be worthwhile to check. Finally, if you are not using all the input pins, you could continue to operate the limit switch on pin 11 and hope for the best.

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I have a breakout board and it appears that the pin 12 connection has failed: when i move my limit switches to pin 11 they work; they don't work on pin 12. Do i need a new breakout board?

https://buildyourcnc.com/Item/electronicsAndMotors-electronic-component-e-stop-button-switch-safety#prettyPhoto/0/

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How do I wire up multiple E-stop to breakout board, does each E-stop need there own pin? If not since there are only 4 screws on stop 2 for no and 2 for nc do you just splice the wires together if your only using 1 pin? Thanks

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.

When wiring the limit switches to our BoB(breakout board), depending in the older model or our revised version (https://www.buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay#prettyPhoto/0/), the older version will need the COM (limit switch) connected to 5V and the NO/NC to your input pin, but with our newer version you will use GND(ground instead of 5V) to common and the same for NO/NC but the setup in the mach3/confi/ports&pins/ is still the same.

Here is a tutorial where you can see how to set up the limit switches correctly (with our older parallel BoB): Part 1:(

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I am attempting to set up limit switches on the 5 axis parallel breakout board that came with my BlackFoot kit. The output pins are driving the motors perfectly, but I can't figure out the input pins. With one lead in the 5V pin and one lead testing the input pins, my multimeter reads 0V for all of the input pins. Shouldn't those circuits be +5V? Where am I going wrong?

You will want to connect the homing switches (which may also serve as your near limit switches) to different input terminals. It's ok to add more limit switches with the home switches, but each home should be on independent inputs. For example, connect home X and any other limit switch to IN1, connect home Y and any other limit switch to IN2, and so on. This will allow you to properly use the "ref all home" button in Mach3.

Additional Information:


Additional Information:
In the instructions (diagram 1) you show all the home switches connected in parallel? But here you say they need to each have their own inputs. "You will want to connect the homing switches (which may also serve as your near limit switches) to different input terminals." I dont see how the second and third axis can go home if the first axis has already closed the parallel circuit unless they back off a bit until the switch opens up again before the next axis goes to home? My machine has no limit switches so I assume they are home switches.

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[575] I have finally got my limit switches wired and working - thank you. Can they also used as homing switches and if so it it just a question of looping the two inputs on the board i.e. the limit and home terminals IN2 to IN3

NC mechanical switch configuration is supported. You can download the manual from this page (Mach4 plugin and manuals):
https://buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach4-mach3-USB-ethernet-Board

The pokeys57CNC controller has input terminals and pins for limit switches on each of the 8 axes. There are three separate inputs per axis, two for the actual limits of that axis, and one for the home position.

Connect each switch between the GND terminal and its respective axis limit terminal/pin. For instance, the limit switch will typically have three leads, COM, NC, and NO. In an NC configuration, the NC connects to the terminal/pin, say, Axis 1 lim +, and the COM connects to the GND terminal.

In Mach4, in the new device wizard, make sure to specify the correct option on the home and limit switches that matches the machine configuration.



Additional Information:
can you use one switch per axis for home only?

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Hello, I am trying to configure Home and Limit switches using the Pokeyes57cnc and NC switches. I am confused on the procedure of setting this up. wiring to the board and setting up in Mach4. Can you direct me to a tutorial or offer some suggestions? Thanks Dale

To home the z-axis using a plate:
- Connect the end mill using a large clamping device like an alligator clip with a wire connected to GND.

- Connect the plate (solder a wire to the plate) to one of the input pins.

- You can use the autoset to setup that pin in Mach3 simply by touching the two together once connected to the pin and GND.

Alternatively, the end mill can be connected to the pin and the plate connected to GND as long as there becomes a complete circuit when the end mill touches the plate.

To setup homing for the Planet-CNC homing and limits, go to the Planet-CNC Machine setup page which explains the process step by step: http://www.planet-cnc.com/faq/machine_setup/

Customer Response:
How do I get homing on z to work with planet cnc software using build your own usb board. I have gone to planet website and followed the instructions provided but my software will not allow entries in the required fields they are grayed out is it because I am not using planet-cnc's board, I have used this method for years with Mach3 and would like to use it with the usb board and software.

Answer:
Just received information from the developer. The instructions on how to use a plate for z-axis homing (moveable sensor) can be found here:

http://www.planet-cnc.com/faq/moveable_sensor/

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How do I get Homing on Z to work with Plate and Ground using Buildyourcnc usb board all the entries for the sensor in planet-cnc are grayed out. I am using input z- and I purchased the software

You can add a limit switch to either the USB or the parallel board. Please refer to the product pages for these items to view wiring diagrams.

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I want to add limit switches but I have no connections on the breakout board. Can I use a usb interface board for the limit switches as well as the parallel port for the running?

You can add a limit switch to either the USB or the parallel board. Please refer to the product pages for these items to view wiring diagrams.

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I want to add limit switches but I have no connections on the breakout board. Can I use a usb interface board for the limit switches as well as the parallel port for the running?

(These steps are to be taken with precaution, due to the fact that we do not know the model or manufacturers specifications for your BoB)

Here is a link to our CNC electronic videos(

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I have a CNC Machine from China, and the Breakout Board is not Labeled. Is there any way to test the board using Mach3 to find out the pin designations? db25 bob

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 Mach3 USB will not work with Linux CNC. You can use our parallel breakout baord instead (if you have a computer that has a parallel port available).

Here is the link to that interface:
https://www.buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay

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Hello. I'm currently building my first CNC router, and I'm powering it with a 3 axis electronics kit that was purchased through your site. I chose to get the Mach 3 USB Breakout board, but now I'm wanting to try to use Linux CNC to work with the computer I have available. Will that work with this board?

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

Each home switch needs to be on a separate input on the Mach3 USB controller. For instance, the x-home on IN1, Y-home on IN2, and Z-home on IN3. You can still wire the other switches on the same input, for instance, the IN can contain the X-home and X++ limit. The X, Y, and Z homes can still serve as the limit --.

Additional Information:
So I need 3 of 4 INs only for the home switches??? The remaining one for ++? What about E-Stop and Probe?

Additional Information:
Please have a look at the wiring diagram you show below. There are all limit switches at IN2 and all home switches at IN3. Makes sense to me.

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[575] I have two limit switches for X, Y and Z axes connected to only one input terminal. As usual, I also want to use them as home switches. But after the first axis touches its home switch, I get an emergency stop because of "activating a limit switch". Mach 3 normally knows when to use a limit switch for homing. Which detail in the depths of Mach 3 did I forget?

I would not recommend slaving an axis using the method of taking an additional axis from the USB interface. Instead, wire both drivers to a single axis on the USB interface. This will insure perfect signal output to both drivers. If you requre the motors to spin in opposite directions, simply wire one of the motors to the driver reversing the coil A and B connections, or use a hex inverter (https://www.buildyourcnc.com/tutorials/Tutorial-Two-Motors-Spinning-Oppositely-On-Single-Axis).

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I purchased a USB Breakout board, motors and drivers, paid for CNC USB Controller Software and I CAN NOT "Slave" an axis, but there is an option to do that. The moment I connect USB Breakout Board "Slave" option becomes shaded and I can no longer select it (becomes not functional). What is going on? Need help asap. Thanks

Have you tried a different input pin?

Customer response:
I've tried all pins: 10, 11, 12, and 13. I get the same non-response in each case.

Recommended action
There may be a problem with the board. If you are using our parallel breakout board, we can ship you a replacement (call us), otherwise, you will need to determine the problem with the vendor of the breakout board you are using.

Additional Information:
I have tried 3 different breakout boards from 3 different providers and they all do the same thing My limit switches are microswitches wired NC with each axis wired to the BO Board. I have checked each circuit and all is OK to the BO board. each circuit has continuity at the board and when any switch is pressed the circuit breaks. Mach 3 does not recognise that the switches are even there. They are configured as active low Do you have a suggestion.

Additional Information:

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I'm having trouble getting Mach3 to recognize my limit switches. I've eliminated everything back to the breakout board. I can directly connect Input 10 to GND on the breakout board while Mach3 is in autorecognize mode and Mach3 doesn't acknowledge anything.