I can not configure limits and home

Hello everybody,

I am a new linux user.
I made a CNC from old printer parts it have some accuracy problems but run with Mach 3. I have two switch per axis one for max limit and another one for home . Both are wired in serial to the same pin in the port . This configuration run well with Mach but I can translate to Emc2.
I tried to confogure of all ways in the wizard but in the program always appears some " Joint 1,2,3 on limit switch error" . In some configuration I can homing well but when I want to move the axiis the switcht release and give again the error. Could you someone help me?

Thanks in advance.

you may need to invert the parallel port pin.
can you get the limits to work without homing?
are your axis moving in the right direction to begin with?

Hello marley,

Thaks for your e-mail.

1 How can I do that . I have tried invert the home in the wizard but the the home change to the opposite place.
2 I tried in EMC2 unhoming but I have the same problem with the switch.
3 Yes the axis move in home direction touch the swith then go in the opposite side and touch again.( i tried to change in the configuation " same " but do not work well.)

Best reards.

Andy is right I meant inverting the parallel port pin.
When i asked if the axis is moving in the right direction I meant does the axis (when jogged) move in the right direction.
When homing it can seem like it is going in the right direction but what is happening is it thinks it is on the home switch already.
If it thinks its on the home switch already EMC will BACK OFF till the switch trips then try again.

so I would make sure the axis moves in the right direction when jogging ( even if you have to temporarily disable all homing and limits)
You can watch AXIS gui to see if your axis is moving right, but remember AXIS gui shows movement as if the TOOL is moving and for most
machines its often the table that moves (in the opposite direction)
Then I would add limits ( both limit x ) and see if you can jog without errors and carefully see if the limit switches work.
EMC expects that the limits switches signals are FALSE when NOT active but this is after any inversion of the interface or inverting of the parallel port.
If the inversion is wrong you should get an error right away. If you do, invert the parallel port pin , there is a check box on the parallel port page in stepconf for this.
Assuming you get that all working then add homing (both + home x)
If it searches in the wrong direction then negate the search velocity.
hope that helps. lets us know if it doesn't
Chris M

Thanks Andy and Cmorley,

I have tried again. I change "Both limits and HOME", I inverted DIR in the check box. I checked the axis when I jog they go in the right way the same that I can see in the AXIS gui ( screen) . I have tried all the ways. Sometimes it homing but the switch is push, I jog the switch release and appear the error.
I use the normally close contacts of switch.

I have tried too change the values of home switch location minor ,equal home limit , equal to table travel but nothing .

I am thinking to change the wiring of switch.

Regards

We meant to invert the limit switch on the parallel port page.
Sorry if that was not clear.

A systematic approach to this is really the only way i can help.
Did you try what I asked, in the order I suggested ?
If you did at what point did it fail. I'm still pretty sure it's the inversion of the limits

If switching to normally open switches fixes it, then for sure that was the problem.

Normally closed switches is what you really want to use. I'm not sure how the switch is
connected to the computer. if the BOB doesn't invert the signal or you connected the switch
directly then the signal to EMC will be high, which tells EMC you are on the home switch.

Chris M

Dear Cmorley,

Thanks for your e-mail

When you said that "We meant to invert the limit switch on the parallel port page ". I have invert the switches in the port page In the little box ( wizard).

You are very clear the problem is my bad English

I do in the order that you said I hope.
First I have configured the mill without switches
After I have invert the Y DIR in order to the Y axis move in the right way . then I jogged and all axis go in the direction I want.
Then I have configured the switches ( Both limits and Home). But the errors still appears.

The switches are normally closed. I must configure this ? Where?
The switch are connected to the PC through a interface:
www.esteca55.com.ar/proye-interfazcnc12.html


Sorry but What is BOB?

Thanks for your patience.

Regards.

A BOB is a break out board.
like this: www.pmdx.com/
oh yes the board your using is what I meant.



Did you invert the limit switch like this screen shot? (invert is checked by the limit switch)

Hello Cmorley,

Yes this that I do. When I invert this the home change to the opposite side.

Regards.