Any PLC

sundar_recr

Member
S
Join Date
May 2006
Location
Coimbatore,Tamilnadu.
Posts
4
I am having Only one Push button with only one Normally Open Contact. With this i have to switch on & OFf a Output . i.e if i press the push button the output should go to ON state. And if i press the pushbutton Again The Output should go to off state. The process should be repeated.
How can i d the ladder logic for this?
 
It may also be called a flip flop, it depends on the PLC what to use but most have some form of one-shot instruction which is also called a positive (or negative) differential. This is an example of a basic method using a GE Fanuc with a positivie differential coil (the M with ^). I is input and Q is output. This page also offers a flow chart provided by Terry Woods to help explain it.
http://www.patchn.com/flipflop.htm
 
Last edited:
yes, its called a momentary contact, or a free running clock, AB S2:4/x, does yours?
Click to expand...

Do not go there, AB has nothing Siemens does not.

PERSONALLY I do not see what a pulsed function or clock has to do with what was asked.
 
rsdoran said:
Do not go there, AB has nothing Siemens does not.

PERSONALLY I do not see what a pulsed function or clock has to do with what was asked.
Click to expand...

Ron, I am well aware of what Siemens has to offer, he did not say "Siemens" but I would like to know what PLC he was referring to? as for the clock I was referring to a "pulsed function" question by fox not the original question. I would consider a free running bit a "pulsed bit".

504bloke said:
Me neither, but i would hazard a guess that we will find out!
Click to expand...

ya think?

Amr Hassan said:
why don t u se a pb which latchis its position , this would be much easier
Click to expand...
Yes, I would agree, but if you read the original question, he has one N/O contact (momentary) is the way that I took it, so as in my original reply, there have been several debates about toggle (flipflop)

Is everyone having a nice holiday? (in the US)
 
504bloke said:
Is it holidays in the US?

It's Bank Holiday Monday here in the UK, 4 days work only this week.......... :D
Click to expand...

Still a 7day work week here:mad: , but it is a holiday;)
 
Amr Hassan said:
why don t u se a pb which latchis its position , this would be much easier
Click to expand...

Yes, it would be easier, but would only offer a fraction of the functionality. For instance, I often use illuminated momentary PBs to start machines, i.e. the operator pushes the button, the light comes on and the machine starts. They push it again, and the machines stops. But I can also stop the machine automatically based on fault conditions, product counts or whatever, and the button light goes out, requiring the operator to restart the machine. If I used a latched PB and stopped the machine automatically, it just wouldn't "look right" to see the button in the ON position without the machine running. The illuminated momentary button, although very simple, gives more operator feedback.

I pretty much limit latched switches to settings that are mutually exclusive, such as auto mode and manual mode, and that do not directly cause machine motion.

Just my opinion.
 
Then there is the case where a single push-button serves a number of different functions... just like the page-oriented buttons around an HMI. While the HMI is displaying Page-1, the particular button performs "this particular function". While Page-2 is displayed, the same button performs "that particular function". In that case, a mechanically self-latching button is useless.

Since the question was posed in terms of "Any PLC"...

http://www.plctalk.net/qanda/showthread.php?t=22175&highlight=toggle
 
Terry Woods said:
Since the question was posed in terms of "Any PLC"...

http://www.plctalk.net/qanda/showthread.php?t=22175&highlight=toggle
Click to expand...

This has to be some kind of record...the same tread was quoted 3 times.

geniusintraining said:
Ok, http://www.patchn.com/flipflop.htm here are 500 and here are the other 500 http://www.plctalk.net/qanda/showthread.php?t=22175
Click to expand...

geniusintraining said:
Try this by markhommer http://www.plctalk.net/qanda/showpo...34&postcount=24

look at this http://www.plctalk.net/qanda/showthread.php?t=22175
Click to expand...

and now 6, thread =22175 covers it all:site:
 

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