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

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

If you select the Settings Page and select or tick Auto Limit Override - this will allow you to back off the switch.

Additional Information:
limit and home switch

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When the machine hits the limits it stops but the switch is still tripped so clicking the Mach3 RESET button doesn't do anything. How am I supposed to get the machine to move off of the limit switch so I can continue working?

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.

Are you trying to use the MPG (tab), or the keyboard for jogging the motors? You mention 0,0,0, are you trying to home the machine with the "ref all home"?

If you cannot move the motors with the keyboard, check if the jog is enabled.

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[596] I have my motors and limit switches working correctly but I am unable to get any movement from the 'jog step' so that I can set 0,0,0. What should I check

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.

If you already have a Mach3 license, you don't need to purchase another one. The license is connected to you rather than the computer. Mach4 is licensed to the computer, but you are able to have multiple computers for each license, and can be switched from one computer to another.

If you purchased the license from me, you can call (make sure to leave a voicemail), or email to get a re-issued license.

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[575] I have an older CNC (2018) which has been working fine. The Windows 7 PC crashed and I am trying to get operational again using a windows 10 machine. I will have to buy a new license for the Mach 3 so will need to get the interface board I have to talk to MAch 3. Can I get just the disc or is there a place I can download what I need?

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 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.

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.

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!

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?

Considering enlarging the machine, might have its down sides do to the structural integrity of the scratch build machine. Primarily by making the width longer it will start to sag in the center, which will lead to having to redesign the gantry to be more structurally rigid to support the added length. Which then will increase the weight and height of your gantry to support the add size, which will always end up to creating a larger CNC.

We usually do not recommend modifying the scratch build CNC, due to the very limited capabilities, and the structural design of the scratch build. We also do not recommend using longer than 48" ACME screw/leadscrew due to the increasing chance of warping and bending in the ACME screws/leadscrew in the given length.
We do recommend modifying the CNC machines we sell to accommodate the added requests that some of our customers desire, but you will be limited to the width of the gantry with our machines.

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I've read your book and I'm looking to purchase the hardware kit with DVD as well as an electronics kit. I would like my machine to have a working area of at least 24" wide by 48" long. Can I just make the bed (and gantry) wider to accommodate larger priceslike 30"x60"? If so what electronics kit would you recommend?

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

Additional Information:
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.

I can send you a new license. All you need to do is email me at customerservice@buildyourcnc.com and state the name the license is under and I will send you another license.

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I had to reset windows on my computer and in so doing, I lost my Mach 3 program. I tried to re-download it, but the license is expired. How can I reinstall the program? License # 44y5-Version R3.043.062- Bought about May 12, 2020

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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How can I convert from Xylotex to yours, four axis with limit switches. Have parallel PC and steppers on machine.

If you select the Settings Page and select or tick Auto Limit Override - this will allow you to back off the switch.

Additional Information:
limit and home switch

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Hi there, when the gantry bumps up against a limit switch and triggers it, how do you tell Mach3 to allow me to jog the motor away from the limit switch? ie: I can't press RESET because the limit is open.... how do I move it? Thx.

If you select the Settings Page and select or tick Auto Limit Override - this will allow you to back off the switch.

Additional Information:
limit and home switch

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Hi there, when the gantry bumps up against a limit switch and triggers it, how do you tell Mach3 to allow me to jog the motor away from the limit switch? ie: I can't press RESET because the limit is open.... how do I move it? Thx.

Yes, you can use 12VDC for the MAch3 USB controller at the 24V and DCM terminals. I have not tested using 12VDC in conjunction with the ACM and AVI terminals (PWM output) to control the spindle speed. PWM typically requires a reference voltage (from the VFD) and it's own voltage to produce the PWM signal. I am not sure if 12VDC is sufficient for the PWM. I have tested the inputs with 12VDC and they work fine.

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[575] does the 24VDC input actually need 24 VDC if only using the input for homing switches? Can you use 12 VDC? and would it be damaged with a higher voltage than 24 VDC?

Most likely, the driver is not receiving the high or low signal for the direction terminals. The way direction works for an axis is the controller will output a high signal (5V) for one direction and low signal (0V) for the opposite direction. If the signal is always at one signal, say 5V, whether it is commanded in one direction or the other, then the axis will only move in that direction.

To solve this problem, make sure that the wiring is secure at both ends (from the controller to the driver). Also, make sure the Dir+ and DIR- are both wired correctly (i.e. the Dir- is connected to the signal gnd on the controller and the ZD is connected to Dir+ on the driver.

You can use a multimeter to determine the voltage at the ZD terminal by:
- setting the multimeter to DC voltage (the V with a straight line, or dashed line above the V)
- place the black lead on the gnd terminal
- place the red lead on the ZD terminal
- press the page up button and check the voltage
- press the page down button and check the voltage.

You should see the voltage change from 0V to 5V or vice versa.

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Hi I have just set up my machine using a mach 3 USB board I can only get the Z to go in one direction Y and X are Ok I have check wiring and looked at video over and over what have I missed??