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Debounce

 

I ran a short file yesterday about 40 times and the reset was never triggered.

Today I run a long file and 12 mins into the file the reset was triggered.


I had setup both home and limit switches on the X axis.

The Debounce was set to 1000


I have now removed the Limit switch check and am using the switches for homing only.

I have also set the Debounce to 500.


My question is where should the Debounce be set? And if it needs to be adjusted is it better to go up or down?


So far the file has run 25 minutes and no trigger yet. Crossing fingers but so far so good.


I know I seen a video on this somewhere but can't remember where.


Thanks for any help on the subject.


Troy
 

The debounce should be set at 0, imo, ime.

If you get false triggers, the better solution is to fix the electrical noise thats causing this.
Shielded cables ?
Grounded at one end only ?
Proper switches ?

FTP cable is one cheap source.
Debounce is a way to mask the problem.
Sometimes you cannot eliminate the false triggers, and then debounce is the only practical way.

Caps on the switches may help-
Also, any old ups, can be used to isolate the noise from a router, plasma, or noise main motors.
A small ups is not expensive, but I am not sure if the small ones do good isolation.

My ac servos are very noisy, but grounding the shield to the motor frame makes the problem go totally away.

On 01/03/2015 03:46, testfly@... [mach1mach2cnc] wrote:

Thanks for any help on the subject.


Troy
--
-hanermo (cnc designs)
[email protected]
 

The problem with setting your debounce to 1000 is that it can overtravel before stopping. I like to keep the debounce down to around 50.
Dan
Spencer Chase
 

开云体育

i just bought some of these debounce chips for another application but have not tried one yet. even thought they are tiny surface mount, they have just power and in and out switch connections so they should be easy to solder into anything. if the false switch closures are caused by electrical noise, i am not sure these would fix it but they should work for pretty much any switch contact debouncing. i am using hall effect limit/home switches on my machine which i should replace with mechanical switches some day because the hall effect ones are too touchy. when i do, i will use debounce circuits.



On 3/1/2015 2:11 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

The debounce should be set at 0, imo, ime.

If you get false triggers, the better solution is to fix the electrical
noise thats causing this.
Shielded cables ?
Grounded at one end only ?
Proper switches ?

FTP cable is one cheap source.
Debounce is a way to mask the problem.
Sometimes you cannot eliminate the false triggers, and then debounce is
the only practical way.

Caps on the switches may help-
Also, any old ups, can be used to isolate the noise from a router,
plasma, or noise main motors.
A small ups is not expensive, but I am not sure if the small ones do
good isolation.

My ac servos are very noisy, but grounding the shield to the motor frame
makes the problem go totally away.

On 01/03/2015 03:46, testfly@... [mach1mach2cnc] wrote:
>
> Thanks for any help on the subject.
>
>
> Troy
>

--
-hanermo (cnc designs)


--

Best regards, Spencer Chase
67550-Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...

(425) 791-0309
 

I think I would stay far away from this type of solution. These chips are designed to debounce human activated switches. They will introduce a delay that could be significant; they are another point of failure of your safety switches; and in the end do nothing more than Mach3 is already doing when you set the delay greater than zero.

As Hannu wrote, the only safe, long term fix for this problem is to eliminate the noise and/or replace defective switches.

Graham


---In mach1mach2cnc@..., <lists@...> wrote :

i just bought some of these debounce chips for another application but have not tried one yet. even thought they are tiny surface mount, they have just power and in and out switch connections so they should be easy to solder into anything. if the false switch closures are caused by electrical noise, i am not sure these would fix it but they should work for pretty much any switch contact debouncing. i am using hall effect limit/home switches on my machine which i should replace with mechanical switches some day because the hall effect ones are too touchy. when i do, i will use debounce circuits.



On 3/1/2015 2:11 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

The debounce should be set at 0, imo, ime.

If you get false triggers, the better solution is to fix the electrical
noise thats causing this.
Shielded cables ?
Grounded at one end only ?
Proper switches ?
Spencer Chase
 

开云体育

i agree that if mach3 does software debouncing that a hardware solution is not necessary. the circuit i mentioned has a period of 50 ms, i don't think that delay would cause a problem.

i will probably just increase the stiffness of the arm that activated the hall effect switch on the x axis and will stay with them. the other axes have very rigid actuators and there is no problem with them. as long as i am cutting only wood, should not be a problem with metal swarf interfering with the switches. they are probably very repeatable if they are rigidly mounted.

On 3/1/2015 5:21 PM, gebowes@... [mach1mach2cnc] wrote:
?

I think I would stay far away from this type of solution. These chips are designed to debounce human activated switches. They will introduce a delay that could be significant; they are another point of failure of your safety switches; and in the end do nothing more than Mach3 is already doing when you set the delay greater than zero.


As Hannu wrote, the only safe, long term fix for this problem is to eliminate the noise and/or replace defective switches.

Graham


---In mach1mach2cnc@..., wrote :

i just bought some of these debounce chips for another application but have not tried one yet. even thought they are tiny surface mount, they have just power and in and out switch connections so they should be easy to solder into anything. if the false switch closures are caused by electrical noise, i am not sure these would fix it but they should work for pretty much any switch contact debouncing. i am using hall effect limit/home switches on my machine which i should replace with mechanical switches some day because the hall effect ones are too touchy. when i do, i will use debounce circuits.



On 3/1/2015 2:11 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

The debounce should be set at 0, imo, ime.

If you get false triggers, the better solution is to fix the electrical
noise thats causing this.
Shielded cables ?
Grounded at one end only ?
Proper switches ?



-- 

Best regards, Spencer Chase
67550-Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...

(425) 791-0309
 

For a small wood router, I dont think so.
For home switches, or something truly accurate, or fast, yes.

An example, for illustration:

Running at 100 mm /sec, a 0.05 sec delay is 5 mm in movement.
6 m/min or 100 mm/sec is not always very fast, today.

Iirc probing, limits and spindle index are the critical ones, and run under 0.5 ms delays in the ring zero layer.
(at 25.000 Hz, the lowest speed, max delay would be 0.4 ms, by my math).
Faster with hardware boards.

CSMIO runs at 4 Mhz, Pokeys at 25 kHz-125 kHz on motion engine, not sure on internals.
cheers,
h-

On 02/03/2015 18:23, Spencer Chase lists@... [mach1mach2cnc] wrote:
i agree that if mach3 does software debouncing that a hardware solution is not necessary. the circuit i mentioned has a period of 50 ms, i don't think that delay would cause a problem.
--
-hanermo (cnc designs)
Spencer Chase
 

开云体育

aren't you supposed to approach the home switches slowly when homing? i thought homing went close and then did a slow back and forth to set the home accurately?

On 3/2/2015 9:37 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

For a small wood router, I dont think so.
For home switches, or something truly accurate, or fast, yes.

An example, for illustration:

Running at 100 mm /sec, a 0.05 sec delay is 5 mm in movement.
6 m/min or 100 mm/sec is not always very fast, today.

Iirc probing, limits and spindle index are the critical ones, and run
under 0.5 ms delays in the ring zero layer.
(at 25.000 Hz, the lowest speed, max delay would be 0.4 ms, by my math).
Faster with hardware boards.

CSMIO runs at 4 Mhz, Pokeys at 25 kHz-125 kHz on motion engine, not sure
on internals.
cheers,
h-

On 02/03/2015 18:23, Spencer Chase lists@...
[mach1mach2cnc] wrote:
> i agree that if mach3 does software debouncing that a hardware
> solution is not necessary. the circuit i mentioned has a period of 50
> ms, i don't think that delay would cause a problem.

--
-hanermo (cnc designs)


--

Best regards, Spencer Chase
67550-Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...

(425) 791-0309
 

Yes, its a parameter.

I referred to limit switches Re: speed and a 50 ms delay.
Sorry I was not more clear.

On 02/03/2015 19:22, Spencer Chase lists@... [mach1mach2cnc] wrote:
aren't you supposed to approach the home switches slowly when homing? i thought homing went close and then did a slow back and forth to set the home accurately?
--
-hanermo (cnc designs)
Spencer Chase
 

开云体育

if you hit a limit, isn't it pretty much time to reset? why would you care if you were off by a few mm, you probably screwed up if you hit the limit anyway?

i am wondering about all this because i do want to do proper limit switches on my machine at some point so i can home reliably. i will probably stick with the hall effect switches if i can stiffen up the arm that the X axis limit switch uses but if i do use microswitches i might want to debounce them? since mach3 does software debouncing it is probably not a good idea to add another possible point of trouble. i use software debouncing in all of my arduino machines and it works just fine and is very configurable.

On 3/3/2015 2:47 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

Yes, its a parameter.

I referred to limit switches Re: speed and a 50 ms delay.
Sorry I was not more clear.

On 02/03/2015 19:22, Spencer Chase lists@...
[mach1mach2cnc] wrote:
> aren't you supposed to approach the home switches slowly when homing?
> i thought homing went close and then did a slow back and forth to set
> the home accurately?

--
-hanermo (cnc designs)


--

Best regards, Spencer Chase
67550-Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...

(425) 791-0309
 

You would not care.
Also, you need to make sure you dont overtravel into the switch.

On 03/03/2015 16:19, Spencer Chase lists@... [mach1mach2cnc] wrote:
if you hit a limit, isn't it pretty much time to reset? why would you care if you were off by a few mm, you probably screwed up if you hit the limit anyway?

i am wondering about all this because i do want to do proper limit switches on my machine at some point so i can home reliably. i will probably stick with the hall effect switches if i can stiffen up the arm that the X axis limit switch uses but if i do use microswitches i might want to debounce them? since mach3 does software debouncing it is probably not a good idea to add another possible point of trouble. i use software debouncing in all of my arduino machines and it works just fine and is very configurable.
--
-hanermo (cnc designs)
Spencer Chase
 

开云体育

wouldn't you use a switch with an arm that was arranged so it could overtravel without damage? i have some microswitches that are pretty well made with rollers on the end of an arm. they do not have a lot of slop in them and they are snap acting and maybe repeatable?

since i am not cutting ferrous metal is there any reason to not use the hall effect switches?that are already installed and working?? i think they are very repeatable as long as the reference tab does not flop around. the X axis is on a long floppy arm which i think is the original way it was as an Emco machine. there is a little room for a brace to stiffen it.

On 3/3/2015 7:35 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
?

You would not care.
Also, you need to make sure you dont overtravel into the switch.

On 03/03/2015 16:19, Spencer Chase lists@...
[mach1mach2cnc] wrote:
> if you hit a limit, isn't it pretty much time to reset? why would you
> care if you were off by a few mm, you probably screwed up if you hit
> the limit anyway?
>
> i am wondering about all this because i do want to do proper limit
> switches on my machine at some point so i can home reliably. i will
> probably stick with the hall effect switches if i can stiffen up the
> arm that the X axis limit switch uses but if i do use microswitches i
> might want to debounce them? since mach3 does software debouncing it
> is probably not a good idea to add another possible point of trouble.
> i use software debouncing in all of my arduino machines and it works
> just fine and is very configurable.

--
-hanermo (cnc designs)


--

Best regards, Spencer Chase
67550-Bell Springs Rd.
Garberville, CA 95542 Postal service only.
Laytonville, CA 95454 UPS only.
Spencer@...

(425) 791-0309

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