Jul. 07, 2025
Jamie, I’m not sure if you might misunderstand the terminology or just had a doubble typo on your original post.
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The correct term is HOMING. Your post had it as hoNing, I can understand how that woud cause confusion.
By default the x-carve’s home position is all the way forward, to the left with the spindle at the top of it’s travel.
I could easily be mistaken as I understand it, and from my brief experience the limit/homing switches are actually nonfunctional when jogging the axis’s and when in operation under g-code via easel, chilipeppr, or UGS and all 3 axis’s can be run to the end of thier limits (crashing ) in this state and it will throw off the step count screwing up your work piece.
BTW every expert was once a noob!
Jamie
In a standard machine with what Inventables calls a limit switch kit in fact you are wiring up HOMING or Reference switches. These switches as configured in a standard machine DO NOT limit anything. There sole purpose in life is to tell the software where MACHINE zeros are. Once they have done that when you start your machine and tell the software to home or reference they go dormant until the next time you tell the software to home the machine again because you have crashed the machine and lost your reference to machine ZERO.
Those 3 switches will not prevent you from jogging to a hard stop or a Gcode program that has an error that runs the machine into a hard stop. If 1 of those 3 switches is in the way when this happens there is a good chance that switch will be destroyed.
If you want true limit switches configured on your machine you have some work to do. First you have to control the electronic noise that the brushed DC motor that is used for the spindle on the standard machine. Then you need to add 2 more switches 1 on the opposite end of the X and Y axis. Wire the switches using shielded wire. Switches on the X and Y axis are wired in series NC (normally closed) and the Z switch is NC
The 3 original switches should be wired to 3 pins on your controller and a common ground. Because you have added a new switch on X and Y that are in series with the original switches the wiring travels from the pin to the first switch NC pin and then continues from the switch common pin to the next switch NC pin and then from that switches common pin back to the controller common ground. You do this for both X and Y. So if either switch is triggered it opens the circuit and the software say and event has happened.
Now the fun part you have to figure out how to configure your control software so the software knows that you have it configured as follows
Z homing active, Z+ limit active
X homing active, Z+ limit active, Z- limit active
Y homing active, Y+ limit active, Y- limit active
You also tell the software if you want to home in the positive or negative direction.
Do you need to go to all this trouble, no. But be prepared to fix things when they get broken from crashing the machine.
Also be prepared to ruin more material than is necessary if you had homing and limit switches configured correctly.
Hope this helps
Dave
There’s probably not a day that goes by where you don’t use or encounter a limit switch at home, or at your workplace.
The actuator is the part of the switch that directly interacts with the moving object.
There are 4 general styles of limit switch actuators:
1. Whisker
2. Roller
3. Lever
4. Plunger
Depending on the application, a limit switch may be a combination of 2 of the general styles such as roller-lever.
A limit switch is an electromechanical device operated by a physical force applied to it by an object.
Limit switches are used to detect the presence or absence of an object.
These switches were originally used to define the limit of travel of an object, and as a result, they were named Limit Switch.
For example, a roller limit switch can be used to detect an objext moving past a specific point on a conveyor belt.
When you open the fridge door, a light comes on inside. How does that happen? Yes…. you guessed it! A limit switch is used to detect if the fridge door is open or closed.
Let’s look at another application of a limit switch that you may encounter at home. On many overhead garage doors, there is a limit switch that stops the movement of the door when it reaches its fully opened position.
Contact us to discuss your requirements of limit swith. Our experienced sales team can help you identify the options that best suit your needs.
Alright…now that we’ve looked at a couple of limit switch applications where you might see them in action at home, let’s have a closer look at the device itself.
A limit switch detects an object's physical movement or presence, typically using a mechanical actuator such as a lever or plunger.
Limit switches are electromechanical devices consisting of an actuator mechanically linked to an electrical switch.
When an object contacts the actuator, the switch will operate causing an electrical connection to make or break.
This change signals that a component or part has reached a predefined point or position.
Electrical Limit switches are available in several switch configurations: Normally Open, Normally Closed, or one of each.
Depending on the origin of the electrical schematic, you may see limit switches drawn in different ways.
The International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA) have slightly different symbols.
Let’s have a look inside a microswitch that is a type of limit switch.
A microswitch has 2 limit switches operating together and sharing a common terminal. One limit switch is normally open and the other is normally closed.
To be technically correct, the switch configuration is Single Pole Double Throw, or commonly referred to as SPDT.
The dashed line indicates that both switches are mechanically connected and will operate at the same time.
Be aware that not all microswitches are configured as a SPDT Limit Switch. Some are configured as a Single Pole Single Throw (SPST) limit switch, which has only two terminals.
Alright, let’s connect the microswitch to a lamp circuit. We’ll look at a limit switch wiring diagram where we use 12 volts to operate two different coloured lamps. In the inactive state, the Red lamp is on as the device is not being operated by an object pushing on the trigger.
When the Trigger is pushed the device will activate, and the Green lamp will come on.
Now that you’ve seen the limit switch in action you are probably thinking about some of the applications where you have seen them in action.
For example, you might see limit switches operated by a container on an assembly line, or operated by a rotating machine part or by any number of other moving mechanical objects.
Limit switches could be used to count passing objects, or determining the position of a hydraulic cylinder.
Limit switches are slowly starting to disappear from many industrial applications. They are being replaced by proximity sensors.
Unlike a limit switch, a limit sensor has no mechanical moving parts.
A proximity sensor performs the switching action with electronic switches.
Limit switches will not completely disappear any time soon as they outshine their proximity switch counterpart in their ruggedness and reliable operation in difficult environments.
Generally speaking, limit switches are capable of handling much higher current values than proximity sensors.
What is a Sensor? Different Types of Sensors, Applications
OK, let’s review…
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The RealPars Team
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