If the sensors are NC (normally closed) you can wire them in series. If the sensors are NO (Normally Open) you can still wire them to the same input, but the wiring needs to be in parallel (like a ladder). I have more information on the following video:

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[788] Thanks for the oportunity to ask, I am building a cnc and using npn closed sensors could you help me with the conection of these, do i still connect them in series if i use more than two in each axis. Also you mention that a stop switch should be connected grd and input to the controller would that be done after the 24v power supply. Thanks r

Make sure that the port setting for that output is set to port 3. To do this in Mach3, click config -> Ports & Pins -> click the outputs tab and in the list of outputs, select the output you want to use and set the port to 3.

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I have a single axis motion for my table saw fence. Motor, limit switches and e-stop work fine. I now need to add an air solenoid relay but I cannot get the outputs to work. I have 24v supply connected and tried using the Spindle output on pin 1. But using a multimeter, there is no voltage on the Output 1 terminal.

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.

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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

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

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 will also need to check if the mach3 configuration and the wiring. Since you tested the connection from the motors to the drivers, the connection from the computer to the interface may still be the issue. It could also be the connection from the interface to the drivers, but we test all of these units going out, so I don't believe that would be the problem.

If you have a redfly that uses a parallel cable, you may need to check to make sure the parallel cable is functioning properly, and also, make sure that the interface is also powered using a usb cable.

If you have a usb interface (the terminals will be labeled XD, XP and so on), then there may be a wire not seated correctly in a terminal.

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I plug in my redFly for the first time and after configuring Mach3 and rechecked my settings axes Y and Z are working well, but X is not working, just for testing I plugged in each motor to the Y and Z and they work fine, but no motor works when plug into the X axes of the redFly, also one of the NEMA 24 425 Oz motors dose not turn just jitters.

Make sure to watch this video that I created to correctly connect a VFD to the Mach3 USB controller. Yes, the 10V terminal on this controller is an input. VFDs typically have a 10V output that can be connected to this terminal.

Additional Information:
The video is here:

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[575] I want to run a SAKO VFD SKI780 by means of this break out board. On https://www.youtube.com/watch?v=P6xxHj6qYSA is mentioned that the 10V terminal on the BOB is an input connection and that it ha to be connected with an external 10V supply source to obtain a 0-10V PWM signal on the AVI terminal of the BOB. I this correct?

Did you set them up as limit switches or home switches?

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Not sure where do I check that?

Additional Information:
Go to config, then ports and pins, then input signals.

Additional Information:
The limits are labeled x++, x— for example.

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I'm using Mach3. I have 2 limit switches on X, 2 on Y and 1on Z for retracted/home. I can go to diagnostics and see the switches/inputs working. But when I move with jog or gcode they have no effect. Also I can go right past the soft limits. I must have something turn off but I don't know what.

All USB boards, are tested and checked before shipment for all axis, and inputs. Here is a link with clear instructions on how to setup Planet-CNC (http://www.planet-cnc.com/faq/machine_setup/).

Please check continuity and for any crossover disruption when wiring your board, try to wire each as cleanly and with out crossing any live power wires and or motor motion wires.

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I have a usb cnc driver board on your 1'x3' cnc and i cant get the z+ limit switch to stop the machine in the provided software. It registers the button but doesn't inhibit movement. inversly the button works when selected as '-' for negative movement.

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?

Yes, you can use a corner plate very easily. You will want to make a corner plate that has three independent plates that do not conduct with each other. Each of these plates will be connected to a different input (i.e. IN1 for X, IN2 for Y and IN3 for Z). The end mill or tool that is inserted into the spindle will connect to V- of the 24V power supply, or the DCM on the controller, which is connected to the 24V V-. Then, you can use the ref all home button on the program run screen of Mach3.

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I have the mach 3 USB board running a XYZ router, and a Z touch off (button style @ fixed position). I am wondering if there's a way to also use an X,Y plate that will only be responsible for corner finding. Is the digitize input the only input that can be used for a touch plate?

It's generally acceptable to use one pin for all of your limit switches wired Normally Closed (NC), and another separate pin for a Z probe that is Normally Open (NO). LinuxCNC is quite flexible and allows for mixed configurations of NC and NO switches.

Just ensure you configure LinuxCNC correctly to recognize each pin's logic (Active low or active high). And perhaps run a few tests before running the machine.

Additional Information:
It's generally acceptable to use one pin for all of your limit switches wired Normally Closed (NC), and another separate pin for a Z probe that is Normally Open (NO). LinuxCNC is quite flexible and allows for mixed configurations of NC and NO switches.

Just ensure you configure LinuxCNC correctly to recognize each pin's logic (Active low or active high). And perhaps run a few tests before running the machine.

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[59] is it ok to use one pin for all of the limit switches wired NC and another pin for a z probe that is NO, or do all input pins need to be the same (NC or NO)? I would like to use LinuxCNC but will use Mach3 if necessary. a thanks!

Yes, the Mach3 USB board has two terminals that require 24V connection. Most VFDs have a 24V output that can be used to power this part of the Mach3 USB board.

The V+ and V- on the Mach3 USB is not absolutely necessary to operate the CNC machine/router. The V+ and V- of the Mach3 USB board powers the outputs, inputs, and spindle's speed and control.

Here is the Mach3 USB link for more information:
https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board

The new YL600 VFD we have in stock may not have this 24V output. There is a 12V terminal, but I have not tested that terminal if it outputs 12V, or if it is a 12V input. If you are only conecting limit switches to the Mach3 USB and need to power that portion, 12V will be sufficient.

I will delve into these aspects in far more detail on video.

Thanks and Merry Christmas to you as well!

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Hey Guys, I have a brand new redleaf and 5x. In the final stages of wiring and wondering a few things. Can I connect the Mach3 USB board V+ V- to my frequency inverter (type YL600-2s-2k20)? If so where? Will your upcoming (part 2)video deal with this as well as final connections for limit switches and stop button? Merry Christmas!

The axis and connection information for the 3D Printer Main Board can be found here in the instructions below the product information.

https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-3d-printer-mainboard-FDMElectronics-3dprintermainboard

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I purchased the driver boards and MB shield for the White Ant. None of the headers are labeled. Is there a diagram showing which headers is for which axis? Is there also a diagram showing which pin on the driver is ABCD? I have watched the vids and the boards in them do not match what was sent to me.

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.

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Additional to Question 3444: Additional Information: 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?

The e-stop should be wired like a limit switch and can also be within the same limit switch circuit. Use one of the input pins to create the e-stop circuit.

1. Run a wire from the input pin terminal to the e-stop switch red side (one of the two terminals on the red side). The red side is NC (Normally Closed).

2. Run a wire from the other side of the red side of the e-stop switch back to the gnd terminal (or to the next switch - limit switch, NC terminal, then back to gnd, or to the next NC terminal of the next switch, do you see a recursive pattern here?).

The wire that you use for the connections should be shielded and the shielding and any other loose wire within the cable should be tied to gnd.

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Hi - I have wired in a breakout board (with relay) as per suggested wiring instructions (black toe 2X4). I want to wire in an estop but need some guidance on wiring. Also Mach3 is requesting I reset the estop, which suggests its expecting one? Can anyone help? Thanks. Miles

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?

The 3D main board does not have any writing on the solder mask to which specific 3 pin connections are for the 3 axes. However they do show pin 1 on the board itself, now in the link that was mentioned above and here(https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-3d-printer-mainboard#prettyPhoto/0/) will have the actual axes labeled. They are a bit hard to read, but should be as showed in the picture.
Top(closest to 12v power terminal) to bottom(closest to blue or black capacitor):
X-min, X-max, Y-min, Y-max, Z-min, Z-max, e-stop

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On the whiteant. I have an old/different kit bought from this website. When attaching my x y z limit switches there is no solder mask on the main motherboard to indicate x limit y limit or z limit. I need the limit switch pinout for the main cnc board located here. https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-3d-printer-mainboard

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?