PLC 5 Problem....need help or guidance - PLCS.net

Dexstar · July 20th, 2005, 03:04 PM

I have a process that counts parts that come off of a welder. Right now, we have a SQ.D limit that signals when a part passes the limit wire. My problem is, when the limit bounces, it counts that as a part. What are some avenues I can take while still using the limit. I know I can go with a sensor, but I have "some" programming experience. My thought is a OSR instruction, but I've simmed it out and it doesn't seem to be working. Any tips?
BJ

Hydro Power Guy · July 20th, 2005, 03:13 PM

You need to "debounce" the sensor by means of a timer.

[XIC]sensor------(TON)--

[XIC] TON.DN-----(Increment part count)--

hd_coop · July 20th, 2005, 03:19 PM

Quote:

Originally Posted by Dexstar

I have a process that counts parts that come off of a welder. Right now, we have a SQ.D limit that signals when a part passes the limit wire. My problem is, when the limit bounces, it counts that as a part. What are some avenues I can take while still using the limit. I know I can go with a sensor, but I have "some" programming experience. My thought is a OSR instruction, but I've simmed it out and it doesn't seem to be working. Any tips?
BJ

You could program some sort of debounce. Either use your limit switch to start a short timer and use that timer's done bit. Or use a timer that starts when the limit switch turns off and have a debounce that says the switch must be off for xx amount of time before counting the signal again. hope that made sense, if not let me know

DanielCamacho · July 20th, 2005, 03:51 PM

Try this...

Alaric · July 20th, 2005, 06:13 PM

Daniel, your example will upcount on the first scan.

I recommed this approach.

Its simpler and it functions with the on transition, as opposed the off transition, of the switch.

Regards.

July 20th, 2005, 06:23 PM

or you could use a photobeam proximy switch, problem solved

DanielCamacho · July 20th, 2005, 07:44 PM

Quote:

Originally Posted by Unregistered

or you could use a photobeam proximy switch, problem solved

BTW... this solution costs $$$$ programming is only a few minutes of time...

Mickey · July 20th, 2005, 07:52 PM

What input module do you have. Some have build-in filtering to handle this effect.( Debounce filter)

Rupic · July 20th, 2005, 08:14 PM

Some Body Know This Plc?? What You Say Me About?

Dexstar · July 22nd, 2005, 10:23 AM

I have a plc 5/40 with a 1771IAD input card

Mickey · July 22nd, 2005, 02:00 PM

look here
http://literature.rockwellautomation...%20-%20English

or

bioplc · August 9th, 2005, 04:46 PM

Alaric,

Do you this your logic will work with delay time? Can u please tell me how it counts after a delay?

regards

bioplc · August 9th, 2005, 04:47 PM

Sorry..

typo

do you think (instead of do you this)

thanks

russrmartin · August 10th, 2005, 03:56 AM

I know the question was to try to solve the problem with programming, but it really seems to me that any switch that goes made and rattles into an on state after the part passes either is worn out, or needs tension adjusted, etc. I've seen millions of limit switches, as most of you have, and I wouldn't consider using a single one that when the actuator is releases, bounces around enough to change states. I suggest you look at the switch, I would think it's either worn out, or needs adjustment.

Russ

July 20th, 2005, 03:04 PM	#1
Dexstar Member Join Date: Jul 2005 Location: Elkhart, Indiana Posts: 4	PLC 5 Problem....need help or guidance I have a process that counts parts that come off of a welder. Right now, we have a SQ.D limit that signals when a part passes the limit wire. My problem is, when the limit bounces, it counts that as a part. What are some avenues I can take while still using the limit. I know I can go with a sensor, but I have "some" programming experience. My thought is a OSR instruction, but I've simmed it out and it doesn't seem to be working. Any tips? BJ

July 20th, 2005, 03:51 PM	#4
DanielCamacho Member Join Date: Mar 2005 Location: Monterrey Posts: 206	Sample... Try this... __________________ "If there is a problem, there is a solution. If there is no solution, then there is no problem." - unknown Daniel Camacho

July 20th, 2005, 07:52 PM	#8
Mickey Member Join Date: May 2003 Location: Palmdale,Ca Posts: 4,759	What input module do you have. Some have build-in filtering to handle this effect.( Debounce filter) __________________ Mickey If you want happiness for an hour-take a nap. If you want happiness for a day-go fishing. If you want happiness for a month-getmarried. If you want happiness for a year-inherit a fortune. If you want happiness for a lifetime-help someone else. ----- Chinese Proverb

July 20th, 2005, 08:14 PM	#9
Rupic Member Join Date: Jul 2005 Location: Buenos Aires Posts: 1	Entrelec Schiele Ps 200 Some Body Know This Plc?? What You Say Me About?

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July 20th, 2005, 03:13 PM	#2
Hydro Power Guy Member Join Date: Jun 2005 Location: York, Pennsylvania Posts: 130	You need to "debounce" the sensor by means of a timer. [XIC]sensor------(TON)-- [XIC] TON.DN-----(Increment part count)--

July 20th, 2005, 06:13 PM	#5
Alaric Member Join Date: Apr 2005 Posts: 3,979	Daniel, your example will upcount on the first scan. I recommed this approach. Its simpler and it functions with the on transition, as opposed the off transition, of the switch. Regards.

July 20th, 2005, 06:23 PM	#6
Unregistered Guest Posts: n/a	or you could use a photobeam proximy switch, problem solved

July 22nd, 2005, 10:23 AM	#10
Dexstar Member Join Date: Jul 2005 Location: Elkhart, Indiana Posts: 4	I have a plc 5/40 with a 1771IAD input card

August 9th, 2005, 04:46 PM	#12
bioplc Member Join Date: Jul 2005 Location: tampa Posts: 97	Alaric, Do you this your logic will work with delay time? Can u please tell me how it counts after a delay? regards

August 9th, 2005, 04:47 PM	#13
bioplc Member Join Date: Jul 2005 Location: tampa Posts: 97	Sorry.. typo do you think (instead of do you this) thanks

August 10th, 2005, 03:56 AM	#14
russrmartin Member Join Date: Aug 2002 Location: Eastman, Wisconsin Posts: 706	I know the question was to try to solve the problem with programming, but it really seems to me that any switch that goes made and rattles into an on state after the part passes either is worn out, or needs tension adjusted, etc. I've seen millions of limit switches, as most of you have, and I wouldn't consider using a single one that when the actuator is releases, bounces around enough to change states. I suggest you look at the switch, I would think it's either worn out, or needs adjustment. Russ

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