Sumtor Control Board - homing/limit switches

[Roy-J]

Hi,

I have a Chinese 6040 4 Axis CNC router that I would like to fit homing/limit switches to. The mechanical side of things I can manage but for me it's not quite the same with the electronic side of it. So I am hoping I may be able to find the answers to my questions within this forum.

I have attached a photo of the Mach 3 USB control board, the only identifying mark is SUMTOR. I have visited their website but the board is not shown within their site, an email request to both Sumtor and the machine supplier has brought no response.

My questions are as follows.
1) Can anyone identify the model of this board?
2) Is there the facility on this board and if so where to connect the homing/limit switches to?
3) If there is the facility to connect homing limit switches could this board also support optical limit switches?

Kind Regards

Roy

[Clive S]

Welcome to the forum Roy

I am not familiar with this bob but it does look like you can connect switches to the inputs (in 1) next to the Sumtor logo.

I am sure one of the others will chime in shortly.

[Roy-J]

Thanks for your welcome Clive.

Your reply is encouraging in that it seems I can use this board for the limit switches. The input terminal (IN1) I notice has my tool setter connected to it, which I guess works in a similar way to how the limit switches work. Would I be right in thinking that all the switches would connect to this one input terminal and the ground to the OV terminal. If that is correct then the wiring would be straightforward even for me, if using micro switches. I would be still keen to find out if I could use the optical switches I have here which have a third wire for which I guess would be the signal wire.

Regards

Roy

[Clive S]

Thanks for your welcome Clive.

Your reply is encouraging in that it seems I can use this board for the limit switches. The input terminal (IN1) I notice has my tool setter connected to it, which I guess works in a similar way to how the limit switches work. Would I be right in thinking that all the switches would connect to this one input terminal and the ground to the OV terminal. If that is correct then the wiring would be straightforward even for me, if using micro switches. I would be still keen to find out if I could use the optical switches I have here which have a third wire for which I guess would be the signal wire.

Regards

Roy

No. You would need to connect them to the other inputs (in 2 to ....) and then set them up in Mach3 under the correct section.

Not sure what optical switches you have. You could use sensor like :- https://www.ebay.co.uk/itm/Inductive...EAAOSwqMdcvJ7e

There are two types pnp and npn they can also be got from China much cheaper.

The trouble with these are you might require another power supply say 12-24 V for them.

[Roy-J]

I think it would be simpler and easier for me to stick with micro switches.

So that I am clear on this the connections would be made as follows?

2 micro switches for the X axis into IN2 (already occupied by the emergency stop switch)
2 micro switches for the Y axis into IN3
2 micro switches for the Z axis into IN4
All configured in Mach 3

Sorry if I am confusing the matter it's just electronics are not my strong point here.

Regards

Roy

[Clive S]

I think it would be simpler and easier for me to stick with micro switches.

So that I am clear on this the connections would be made as follows?

2 micro switches for the X axis into IN2 (already occupied by the emergency stop switch)
2 micro switches for the Y axis into IN3
2 micro switches for the Z axis into IN4
All configured in Mach 3

Sorry if I am confusing the matter it's just electronics are not my strong point here.

Regards

Roy

I would wait for a little longer and see if one of the electronic guys show up.

It might be possible to connect the three home switches to one input.

https://www.machsupport.com/forum/in...?topic=31845.0

edit: It would be good to quote the other names next to the inputs as the cable is obscuring them

[JAZZCNC]

Hi Roy,

You can do this several ways, ranging from using just 1 input and 3 switches(4 if twin motors) or upto 10 switches with each axis using 3 inputs.!!

In your case the best option would be to use just 2 inputs. One for the limits and one for the Homes. Use separate switches for Homes and Limits.
I would Leave the E-stop on it's own Input and use separate for limits/homes.

The Limits you would wire all the switches in series using NC (normally closed) switches. Series meaning the first switch connects to the second and so on like a daisy chain. This way if any one switch gets tripped the circuit is broken and Mach3 see's the trip.

The Home switches you will wire in parallel, meaning each switch goes to the one Input.

You can do this because when Mach3 Homes it only moves one axis at a time and it doesn't care which Input it see's triggered, it just watches the Input it's told to watch.
So you set each Axis to watch the same Input when homing. So when for instance your homing X axis you could actually trip the Y axis switch and Mach3 will think it's the X axis Home postion that tripped because that's the axis it was moving.

Obviously if you wanted you could assign a separate input to each Axis and Home all of the axis at same time, but by default Mach3 only moves one axis at a time, starting with Z, then Y and X, so the above works. To move all 3 at same time would require a tweak to a file in Mach3 and it's also wasteful of Inputs.

There is one last option which uses just one input and one switch on each axis for both Limits and Homes.

To do this you have the switch travel with the axis and at each end of travel you have a target the trips the switch. The switch will also need to NO type so the Homes will work.
The down side to this being the NO switch isn't has safe for the limits because if a wire breaks or the switch gets damaged you won't know about it until it doesn't work when hit. Using NC type for limits is much safer. Hence why I would use two inputs with NC Limits and NO Homes.

Edit:

Another option is to only fit HOME switch and set Softlimts within Mach3. Softlimits will keep you from crashing the machine provided you HOME the machine when first turned on.
To be honest even if you have LIMIT swithces fitted I would set Softlimits as they won't allow you to crash the machine, even if you deliberatley tried to crash it they won't let you and bring the machine to a nice controlled stop when comes to end of travel. Mach3 also checks the G-code and warns you if the code exceeds the Softlimits.

[Roy-J]

Hi JAZZCNC,

Thank you for your valued reply.

That was a very clear and concise explanation, with options, on how to wire up the homing/limit switches. I now have a much better understanding of what I need to achieve.

However, I am due to my lack of experience, still unclear as to where to make the physical connection/s from the micro switches to the BOB (shown in my attached photo above), I am worried about this part more than anything as I don't want to fry anything by making the wrong connections.

I hope you may be able to help me further with clear guidance as to where to make the required connections on my board. One thing I am sure of though is that I have certainly found the right place to be for this sort of expert help.

Many thanks for your help.

Kind Regards

Roy

[JAZZCNC]

However, I am due to my lack of experience, still unclear as to where to make the physical connection/s from the micro switches to the BOB (shown in my attached photo above), I am worried about this part more than anything as I don't want to fry anything by making the wrong connections.

Hi Roy,

I don't know this board at all but It's simple enough if just using Micro switches and just like you thought, take wire from 0v thru the switch back to the Input you want to use.

I've attached a quick diagram showing the wiring for both.

Then In Mach3 -- Config -- ports n pins -- Input signals set each axis limit to same pin number ie:
X ++ = 3
X - - = 3
Y ++ = 3
Y - - = 3
Do the same for HOME Pins ie:
X Home = 4
Y Home = 4
Z Home = 4

Hope this helps.

[Roy-J]

Hi JAZZCNC,

You have made that all very clear for me to the extent that I feel ready to undertake this project one all the parts have arrived.

Can I just clarify that although your diagram shows 3 limit switches I can protect both ends of all 3 axis travels using 6 switches?

I wish to use your suggestion of using separate limit and home switches, if I do how should they be mounted to prevent hitting the limit before hitting the home switch, or vice versa? Or can I mount a home switch and limit switch on top of each other and Mach 3 sort out which switch is activated when either homing or hitting the limit? I hope I have explained this question correctly here.

Thanks and Regards

Roy