Home/ Limit switch bounce

[spokes]

Is there anything in EMC2 that compensated for home and limit switch bounce. I get errors often when trying to home saying that the switch was active before homing once it hits the switch the first time.
Also, for the limit switches, they always seem to trip when the table is in operation even though the table is nowhere near them. I've used capacitors across the switch and at the connection on the controller but they still falsely trip. I've tried NO and NC with the same results.
Dan

[wendtmk]

Originally Posted by spokes Is there anything in EMC2 that compensated for home and limit switch bounce. I get errors often when trying to home saying that the switch was active before homing once it hits the switch the first time. Also, for the limit switches, they always seem to trip when the table is in operation even though the table is nowhere near them. I've used capacitors across the switch and at the connection on the controller but they still falsely trip. I've tried NO and NC with the same results. Dan

Afraid I'm not much help on the first problem, but something has to be tripping your limit switches. How much vibration is present when the table is in operation? What kind of limit switches are you using?

Mark

[wendtmk]

Ah, just thought of something - on your first problem - are your home/limit switches combined?

Mark

[spokes]

Right now I have the limit switches disabled and am only using home switches. They still bounce and are occasionally difficult to get a good home with them.

[wendtmk]

Originally Posted by spokes Right now I have the limit switches disabled and am only using home switches. They still bounce and are occasionally difficult to get a good home with them.

Are you setting your home right on top of your home switch? If so, do you really need your home on top of the home switch? Can you offset your home position say, maybe .2500" from your home switch?

Walk me through what is actually happening in your home sequence.

Mark

[spokes]

Right now the home is triggered by the switch going from off to on so I guess it is right on top of the home. Is there an offset setting in EMC2 that I missed? I will get details of the exact error message generated when homing later today.

[wendtmk]

What I meant was what is your homing sequence? Post your ini file segments for homing on each of your axes.

Here's a good section in the docs that deals specifically with homing, and the variables you can use in each of the homing sections:

LinuxCNC.org - Homing Configuration

Look at sections "0.1.3.6 HOME_OFFSET" & "0.1.3.7 HOME" for information on how to set your "home" position.

Mark

[spokes]

I'm showing an offset of 1" on Z which is causing the most trouble. However, when the unit homes it stops right on the switch.
I'll read up on the document you linked to.
Thanks

[Torsten]

Originally Posted by spokes I'm showing an offset of 1" on Z which is causing the most trouble. However, when the unit homes it stops right on the switch. I'll read up on the document you linked to. Thanks

Just guessing here, Home and home offset are set to 1." on the z-axes.
If your switch is located all the way up, then 1." would be outside of travel?
Did you try diffferent Values here for example Home = 0. and Homeoffset=-.25" seams to make sense to me.
As in hit the switch then back of .25 and call this 0.
May be worth a Try.
Good Luck

[spokes]

I sent the wrong file by mistake. The offset is 0 currently. I tried it at .125 and .250 but all that did was move the axis by that amount after the homing was completed.
The error I get when zero fails is "Home switch active before start of latch move"
I changed the velocity to a lower value and will see how it goes. I still think the switch is bouncing causing the error above. I have some circuits that I will try to filter the bounce and see how that goes.

[chester88]

here is EMC's software debounce component:
DEBOUNCE
the homing error is intermittent?
try shielded wire on your limit switches properly grounded.

[spokes]

The wire is shielded and grounded as it should be, I think I just have cheap switches. Where do you put the debounce code, do you need to use Classicladder or just add it to the ini file on the home line?