Need Help Setting up Homing and Limit switches (Gerrys 2010 screen set. )

Mach3, Gecko 541, Smoothstepper, C25S BOB

I have ran my CNC for 12 years manually, no limit,home switches, or soft limits. Now I have to set them up before I go any further in setting up the 2010 screenset.

Below are two wiring diagrams which one should I be using?

A, normaly closed.
BTW limit/home switches have ho connection with screen set. They are related to Mach and its functionality.

Hi,
the wiring rather depends on how many inputs you have to spare on your BoB/controller.

I am completing my new build mill, my second, having made a mini mill seven years ago, with my own BoBs but with an ESS and Mach4. This build has 32mm
ballscrews, 750W AC servos, 100+kg cast iron axis beds etc. So for this project I've been a lot more careful about Home and Limit switches than I was
with my previous machine.

I have two Limit switches per axis and one Home switch per axis for total nine switches for three axes. Each switch is NC on its own input, ie I have devoted
nine inputs to Limits and Homes. You might think that seems like a lot of inputs....but then again the ESS has plenty of inputs to spare so why not use them?.
In the early days of hobbyist CNC when people use a parallel port it was necessary to combine switches in strings to reduce the number of circuits down to the number
of available inputs. Controllers like the ESS and C25 BoBs mean we don't have to be that frugal anymore.

You posted a circuit diagram with two switches in series, and that would certainly work. If the circuit opens, because either of the Limit switches activated or a break
in the wiring the Mach will Estop....as it should. But Mach won't know whether the X-- or the X++ limit activated. Its a small detail but if you have one switch per circuit,
ie two inputs, then Mach would know which Limit activated and would prevent you from jogging in a direction that would see the overlimit event get worse while allowing you to
jog in the direction to get within the Limits.

You might also ask why have a separate Home switch. Mach it quite adept at treating Limit switches as Home switches when in Homing mode.....it must disregard the
Limit switch circuits while this is happening, and your machine is temporarily unprotected by Limit switches. Whereas if you have a separate Home switch, again on its
own input Mach will never be confused about what is a Limit event and what is a Home event.

Given that I have made my own BoBs gives me greatest flexibility with regards to inputs and outputs. I have split the BoB into two boards. The first board has input
from port 1 of the ESS. I have used its 12 outputs, 10 as Step/Dir for 5 servos (only using three currently), and the other two outputs for a ServoEnable commoned
to all five servos, and an AlarmReset again commoned to all five servos. The ports five inputs have been used as an Alarm signal from each of the five (possible) servos.

The second BoB board accepts the two remaining ESS ports, configured as pins 2-9 as inputs for both ports. Thus this board has 24 inputs (2 x 12) and 10 inputs (2 x 5)..

As previously discussed I've devoted 9 inputs to Homes and Limit. I have two inputs for Estop and Feedhold, another input for a probe.. Thus I have committed 12 of my
available 24 inputs. I have two outputs for the spindle, one for the relay and one for PWM, and yet another output for the coolant pump. Thus I have committed 3 of the available
10 outputs, not counting the Step/Dir/Enable/AlarmReset outputs of port 1.

All-in-all the ESS gives you considerable flexibility to wire Homes and Limits to suit what you deem as best practice. My definition of best practice is one switch, one input.....
no confusion about operating modes....its either a Limit OR a Home and no doubt about it.

Craig

Subject to available inputs, I am also a fan of seperate sensors for max limit, min limit and home. The Mesa 7i76e I use with linuxcnc has 32 inputs and 16 outputs without adding on any daughter cards so there is plenty to go around.
I'm not sure how your system works but I found using a shared home/limit switch reduced available travel because the axis had to be moved off the limit switch or it would trigger a limit error when it came out of homing..

Quote:

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Originally Posted by Mr.Chips

Mach3, Gecko 541, Smoothstepper, C25S BOB

I have ran my CNC for 12 years manually, no limit,home switches, or soft limits. Now I have to set them up before I go any further in setting up the 2010 screenset.

Below are two wiring diagrams which one should I be using?

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On a side note to the other guys.
Normally Closed are the preferred type of switch used on limits.
Circuit A (series to 1 input) only works with Normally Closed (NC) type switches. The entire circuit is closed so if any 1 switch opens, the entire circuit opens.
Circuit B (individual) works with both NC and Normally open (NO) type switches. But as said by others earlier, you need more inputs available.


For another note. More than one NO type switch can also be used on a single circuit, these get wired in parallel instead though. The entire circuit is open and any 1 switch will close it. If this type is wired in series the circuit is always open even if a single switch is closed.

Quote:

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Originally Posted by joeavaerage

Hi,
the wiring rather depends on how many inputs you have to spare on your BoB/controller.

I am completing my new build mill, my second, having made a mini mill seven years ago, with my own BoBs but with an ESS and Mach4. This build has 32mm
ballscrews, 750W AC servos, 100+kg cast iron axis beds etc. So for this project I've been a lot more careful about Home and Limit switches than I was
with my previous machine.

I have two Limit switches per axis and one Home switch per axis for total nine switches for three axes. Each switch is NC on its own input, ie I have devoted
nine inputs to Limits and Homes. You might think that seems like a lot of inputs....but then again the ESS has plenty of inputs to spare so why not use them?.
In the early days of hobbyist CNC when people use a parallel port it was necessary to combine switches in strings to reduce the number of circuits down to the number
of available inputs. Controllers like the ESS and C25 BoBs mean we don't have to be that frugal anymore.

You posted a circuit diagram with two switches in series, and that would certainly work. If the circuit opens, because either of the Limit switches activated or a break
in the wiring the Mach will Estop....as it should. But Mach won't know whether the X-- or the X++ limit activated. Its a small detail but if you have one switch per circuit,
ie two inputs, then Mach would know which Limit activated and would prevent you from jogging in a direction that would see the overlimit event get worse while allowing you to
jog in the direction to get within the Limits.

You might also ask why have a separate Home switch. Mach it quite adept at treating Limit switches as Home switches when in Homing mode.....it must disregard the
Limit switch circuits while this is happening, and your machine is temporarily unprotected by Limit switches. Whereas if you have a separate Home switch, again on its
own input Mach will never be confused about what is a Limit event and what is a Home event.

Given that I have made my own BoBs gives me greatest flexibility with regards to inputs and outputs. I have split the BoB into two boards. The first board has input
from port 1 of the ESS. I have used its 12 outputs, 10 as Step/Dir for 5 servos (only using three currently), and the other two outputs for a ServoEnable commoned
to all five servos, and an AlarmReset again commoned to all five servos. The ports five inputs have been used as an Alarm signal from each of the five (possible) servos.

The second BoB board accepts the two remaining ESS ports, configured as pins 2-9 as inputs for both ports. Thus this board has 24 inputs (2 x 12) and 10 inputs (2 x 5)..

As previously discussed I've devoted 9 inputs to Homes and Limit. I have two inputs for Estop and Feedhold, another input for a probe.. Thus I have committed 12 of my
available 24 inputs. I have two outputs for the spindle, one for the relay and one for PWM, and yet another output for the coolant pump. Thus I have committed 3 of the available
10 outputs, not counting the Step/Dir/Enable/AlarmReset outputs of port 1.

All-in-all the ESS gives you considerable flexibility to wire Homes and Limits to suit what you deem as best practice. My definition of best practice is one switch, one input.....
no confusion about operating modes....its either a Limit OR a Home and no doubt about it.

Craig

---

Thanks for the comprehensive response.
Yes I prefer B it just sounds good having the HOME and LIMIT of different pins, and I didn’t note that all SW were NC.

I went back to my C25S Smoothstepper manual and there are 18 Inputs on ports 1 and 2. See photo.
I’ll wire my CNC up with separate HOME LIMIS (B) and see how that checks out.

...Max Travel limit (if, possible) should be hard wired to each Axis Driver (Amp) to Inhibit the + or - direction so, it is easy to Jog off the Limit Switch easily.

Focus on X a axis until I get it figured out.

Left Limit SW conn to PORT 2 PIN 10 (X - -)
Right Limit SW conn to PORT 1 PIN 10 (X + +) I want it to home on the right side

Both switches show “limit SW triggered” on the screen when triggered. I have to press the reset twice to clear it, is that normal?
What do I do with the X HOME in the ports and pins????

Photo of ports and pins.
ANY SUGGESTIONS?

Quote:

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Originally Posted by machinehop5

...Max Travel limit (if, possible) should be hard wired to each Axis Driver (Amp) to Inhibit the + or - direction so, it is easy to Jog off the Limit Switch easily.

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Thanks I understand

Quote:

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Originally Posted by joeavaerage

Hi,
the wiring rather depends on how many inputs you have to spare on your BoB/controller.

I am completing my new build mill, my second, having made a mini mill seven years ago, with my own BoBs but with an ESS and Mach4. This build has 32mm
ballscrews, 750W AC servos, 100+kg cast iron axis beds etc. So for this project I've been a lot more careful about Home and Limit switches than I was
with my previous machine.

I have two Limit switches per axis and one Home switch per axis for total nine switches for three axes. Each switch is NC on its own input, ie I have devoted
nine inputs to Limits and Homes. You might think that seems like a lot of inputs....but then again the ESS has plenty of inputs to spare so why not use them?.
In the early days of hobbyist CNC when people use a parallel port it was necessary to combine switches in strings to reduce the number of circuits down to the number
of available inputs. Controllers like the ESS and C25 BoBs mean we don't have to be that frugal anymore.

You posted a circuit diagram with two switches in series, and that would certainly work. If the circuit opens, because either of the Limit switches activated or a break
in the wiring the Mach will Estop....as it should. But Mach won't know whether the X-- or the X++ limit activated. Its a small detail but if you have one switch per circuit,
ie two inputs, then Mach would know which Limit activated and would prevent you from jogging in a direction that would see the overlimit event get worse while allowing you to
jog in the direction to get within the Limits.

You might also ask why have a separate Home switch. Mach it quite adept at treating Limit switches as Home switches when in Homing mode.....it must disregard the
Limit switch circuits while this is happening, and your machine is temporarily unprotected by Limit switches. Whereas if you have a separate Home switch, again on its
own input Mach will never be confused about what is a Limit event and what is a Home event.

Given that I have made my own BoBs gives me greatest flexibility with regards to inputs and outputs. I have split the BoB into two boards. The first board has input
from port 1 of the ESS. I have used its 12 outputs, 10 as Step/Dir for 5 servos (only using three currently), and the other two outputs for a ServoEnable commoned
to all five servos, and an AlarmReset again commoned to all five servos. The ports five inputs have been used as an Alarm signal from each of the five (possible) servos.

The second BoB board accepts the two remaining ESS ports, configured as pins 2-9 as inputs for both ports. Thus this board has 24 inputs (2 x 12) and 10 inputs (2 x 5)..

As previously discussed I've devoted 9 inputs to Homes and Limit. I have two inputs for Estop and Feedhold, another input for a probe.. Thus I have committed 12 of my
available 24 inputs. I have two outputs for the spindle, one for the relay and one for PWM, and yet another output for the coolant pump. Thus I have committed 3 of the available
10 outputs, not counting the Step/Dir/Enable/AlarmReset outputs of port 1.

All-in-all the ESS gives you considerable flexibility to wire Homes and Limits to suit what you deem as best practice. My definition of best practice is one switch, one input.....
no confusion about operating modes....its either a Limit OR a Home and no doubt about it.

Craig

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Thanks Craig,
So, you have three SW for the X axis.
Could I cheat and call out the same PORT/PIN numbers a on the ports and pins screen for the right side HOME and LIMIT SW?
If not, there would be two switches on the right side. I can bolt them together, but would they have to trigger at exactly the same time?
Sorry to be so picky, it’s because I don’t want to assume anything, got bit bad before.
Thanks
Hager

Quote:

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Originally Posted by Mr.Chips

Focus on X a axis until I get it figured out.

Left Limit SW conn to PORT 2 PIN 10 (X - -)
Right Limit SW conn to PORT 1 PIN 10 (X + +) I want it to home on the right side

Both switches show “limit SW triggered” on the screen when triggered. I have to press the reset twice to clear it, is that normal?
What do I do with the X HOME in the ports and pins????

Photo of ports and pins.
ANY SUGGESTIONS?

---

On the config screen for homing/soft limits there is a tab that says 'home off'.
This should be the section where the number you put in there is the distance the machine will automatically back off the limit switch and call that position home.
'Home neg' should be the direction it will go. Selected will be neg, unselected will be pos.

I've not set all mine up yet either but that's how it's supposed to work.

Also. The 'reversed' tab can be selected if a motor is running the axis in the wrong direction. This is instead of messing about swapping motor wires around.
Just for future reference.

I forgot.
Towards the bottom of the input signals pins screen there is a signal called 'limit ovrd'.
This is a limit switch override setting. With this checked the machine shouldn't stop when a switch is triggered. Useful for testing switches or if machine won't reset off one so you can jog.


Actually. All this info is in the Mach pdf config manual.
https://www.machsupport.com/wp-conte...all_Config.pdf

Ignore last post.
Just realised my info is for standard screenset.
You were asking about the 2010.
I've not looked at that one for similarities.
My bad guys.

Mr.Chips

Your PM box is full

I just found out, tried several times to delete them but it never gets deleted, sent note to admin.
Sorry about that guess after 18 years it finally got full, LOL.

Quote:

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Originally Posted by Mr.Chips

I just found out, tried several times to delete them but it never gets deleted, sent note to admin.
Sorry about that guess after 18 years it finally got full, LOL.

---

You have to select the messages in the inbox and at the bottom of the page is where you get a choose of what to do with them delete or file them somewhere else

So the inbox and the sent box has to have enough room

Hi,

Quote:

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If not, there would be two switches on the right side. I can bolt them together, but would they have to trigger at exactly the same time?

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If you chose to put the Home switch at the extreme of travel then, yes, you would have two switches 'on top of each other', and, yes, they would activate at the same time.
Home switches do not have to be at the end of travel however. They can in fact be anywhere although it is common to have near one end, if not actually at the end.
My home switches are 4mm 'inside' the mechanical limits and the Limit switches are 2mm 'inside' the mechanical limits.

Lets imagine you have your Home switch 50mm from the top of the Z axis and a Limit switch very near (<2mm) the top. When you <RefAll> your machine it will go to the Home
switch, but instead of resetting the machine coordinate to zero it will set it to an offset you program in. On Machs Home/Limit page you will find a 'Home Offset', and that is what it does.
It means you can put your Home switch exactly where you want for convenience and safety, and yet have the machine coordinates still reflect the extreme end of travel.

Craig

Since day one of my CNC use I have drawn the part in VcarvePro with zero/zero in the center of the drawing. Very rarely used a corner, I just found that to be the easiest. Place the material anywhere on the table and set XY zero to the place on the material I want the piece to be cut from. fool proof for me.

Have never used an offset, or Machine Coordinates. I’ll have to look them up to understand what your describing.

In reading about home/limit SW configurations it seems that I can have two switches on the let’s say Y master axis and define the rear one as Y+ + and the front SW as Y - - and the same front SW as Y Home, if that is true that would save me from wiring a third switch in.

Would it look like this?

Thanks for your help.
Hager

No. Both input pins would be triggered.

It should be like in attached diagram.

Attachment 467132

The CNCZONE Support haven’t cleared my private messages yet.
Mactec54
I’m going with your suggestion for a pin connection for each switch.
I’m using a stepper on the left and right Y axis ball screws.
The right side (MASTER) has homing and limit switches.
The left side (SLAVE) has only a front side homing SW used for squaring the gantry. The left side doesn’t need a rear limit switch because the rear one on the right side takes care of the Y axis limit.
Is this OK?

Please see drawing for wiring ‘

Thanks for your help
Hager