Unlock IN1 input port

[Muzzer]

My first question is: Why are you using home and limit switches? Especially with closed loop drivers, there’s absolutely no need to have limit switches. Just use home switches and set the soft limits. Works perfectly.
-swissi

Without wishing to confuse the specific enquiry, I'd disagree about not needing limit switches. The classic example is where you power the machine off without parking - or suffer a power loss. When you next wake the machine up, it has no idea where the home position (and soft limits) need to be. If you now jog the machine before homing (eg to get it close to home to avoid lengthy homing time), there is no protection against hard stops. If you have a powerful motor, such a hard stop crash can be damaging. Obviously if you have absolute encoders, that can be avoided. However, these are unusual in our sphere.

[martyscncgarage]

It is not advisable to use NO switches.
Do it right and get NPN NC switches. I assume you are using proximity switches. For BOTH HOME ALL and LIMIT ALL.
The premise is that each set of switches is wired in SERIES to complete a circuit. One end on Acorn power supply common and the other on the input.
This will show a GREEN LED on the diagnostic screen.

Go see this post on how to wire NPN NC Proximity switches in series, a video by Automationdirect.com. A good place to buy them too!
viewtopic.php?f=61&t=4342

Marty

[swissi]

... I'd disagree about not needing limit switches. The classic example is where you power the machine off without parking - or suffer a power loss. When you next wake the machine up, it has no idea where the home position (and soft limits) need to be. If you now jog the machine before homing (eg to get it close to home to avoid lengthy homing time), there is no protection against hard stops. If you have a powerful motor, such a hard stop crash can be damaging. Obviously if you have absolute encoders, that can be avoided. However, these are unusual in our sphere.

Muzzer,

I'm not disagreeing with you and every commercial CNC machine should have all the protection possible as we put all available technology into cars to protect drivers from themselves. In the DIY space, many times it's the builder that's using the machine and the builder can choose what safeguards to implement to be comfortable with. That's the great thing about DIY.

So for the benefit of those who are still unclear if they should use limit switches or not, here some more points that could make up your mind:

Restrain yourself from jogging the machine manually while the machine is not homed yet and if you have to do it for some reasons, don't jog anywhere near the travel limits. If the homing process is too slow, there are other, safer options to solve that problem.

One option is to customize the homing script with faster travel speed to the home switch. That speeds up the homing process without the need to manually jog in an unsafe state.

Also what many people don't know, the home switches don't need to be at the end of the travel on an axis. They can be placed anywhere within the travel of an axis. If the home switch is not at the end of an axis, you have to mount it in a way that the machine can pass it and not run into it. In the soft limit table, you then enter the distances the axis can travel in the negative and positive direction from the homing point. That allows you to have the home switch at a very safe distance from the hard stop so it's safe even when you jog manually to the switch. Of course you have to make sure you are at the correct side of the switch when you engage homing so the machine can find the home switch in the configured direction.

To summarize: If you are the type of person who takes selfies as close to a cliff as possible, you are better off with limit switches . If you are a responsible person and can restrain yourself from doing dangerous things, you don't really need them.

Also if you search the forum posts, limit switches can be the source of problems as a faulty switch or loose connection can interrupt job file execution so if you use limit switches you are introducing another potential problem that could flare up in the future.

Just my opinion...

-swissi

[cnckeith]

for years i haven't had limit or home switches on my router, the machine homes from marks which then seek index/marker pulse input for accurate homing. clean and simplified, i have urethane bumpers at end of travel to prevent major damage if for some reason (hasn't happened yet..) there was a mechanical crash. to each his own on this subject, that's way CNC12 supports a wide variety of homing and limit switch setups! )

[Oswaldo]

Thank you all for your advice, but in all the years that I have been working, I have always been safe because it is not unnecessary to put redundant systems, Marty-swssi's appreciation is very clear.
For me this has been a challenge, for a long time and it is the first time that I do the automation of a machine tool and I find it fabulous, going through challenge after challenge.
I will make the adjustments initially without limit switches. And now wait for the NC limit switches to arrive.
With the pandemic and restricted air traffic, it can take several weeks to arrive.
I will be commenting on them.
Thanks for your support.
Oswaldo

Gracias a todos por sus consejos, pero en todos los años que llevo trabajando, siempre he ido a la segura pues no esta por demás poner sistemas redundantes, La apreciación de Marty -swssi son muy claras.
Para mi esto ha sido un reto, desde hace mucho tiempo y es la primera vez que hago la automatización de una maquina herramienta y me parece fabuloso, ir pasando reto tras reto.
Voy hacer los ajustes inicialmente sin finales de carrera. Y ahora esperar a que me lleguen los finales de carrera NC.
Con eso de la pandemia y el transito aéreo restringido, se puede demorar varias semanas en llegar.
Les estaré comentando.
Gracias por su apoyo.
Oswaldo

[martyscncgarage]

Thank you all for your advice, but in all the years that I have been working, I have always been safe because it is not unnecessary to put redundant systems, Marty-swssi's appreciation is very clear.
For me this has been a challenge, for a long time and it is the first time that I do the automation of a machine tool and I find it fabulous, going through challenge after challenge.
I will make the adjustments initially without limit switches. And now wait for the NC limit switches to arrive.
With the pandemic and restricted air traffic, it can take several weeks to arrive.
I will be commenting on them.
Thanks for your support.
Oswaldo

Gracias a todos por sus consejos, pero en todos los años que llevo trabajando, siempre he ido a la segura pues no esta por demás poner sistemas redundantes, La apreciación de Marty -swssi son muy claras.
Para mi esto ha sido un reto, desde hace mucho tiempo y es la primera vez que hago la automatización de una maquina herramienta y me parece fabuloso, ir pasando reto tras reto.
Voy hacer los ajustes inicialmente sin finales de carrera. Y ahora esperar a que me lleguen los finales de carrera NC.
Con eso de la pandemia y el transito aéreo restringido, se puede demorar varias semanas en llegar.
Les estaré comentando.
Gracias por su apoyo.
Oswaldo

No hay problema. ¡Espero que todo te vaya bien!

No problem. I hope all goes well for you!

Marty

[Oswaldo]

Marty thanks for your support
Oswaldo

Marty gracias por su apoyo
Oswaldo