The total response time of the PLC is a fact we have to consider when shopping for a PLC. Just like our brains, the PLC takes a certain amount of time to react to changes. In many applications speed is not a concern, in others though…

If you take a moment to look away from this text you might see a picture on the wall (or maybe your wallpaper at your laptop/desktop). Your eyes actually see the picture before your brain says “Oh, there’s a picture on the wall (or on my laptop/desktop)”. In this example your eyes can be considered the sensor. The eyes are connected to the input circuit of your brain. The input circuit of your brain takes a certain amount of time to realize that your eyes saw something. (If you have been drinking alcohol (only for example, is harom according to Alloh rule) this input response time would be longer!) Eventually your brain realizes that the eyes have seen something and it processes the data. It then sends an output signal to your mouth. Your mouth receives this data and begins to respond to it. Eventually your mouth utters the words “Gee, that’s a really ugly picture!”.

Notice in this example we had to respond to 3 things:

  • INPUT- It took a certain amount of time for the brain to notice the input signal from the eyes.
  • EXECUTION- It took a certain amount of time to process the information received from the eyes. Consider the program to be: If the eyes see an ugly picture then output appropriate words to the mouth.
  • OUTPUT- The mouth receives a signal from the brain and eventually spits (no pun intended) out the words “Gee, that’s a really ugly picture!”

If you want to know about PLC, PLC Programming and Applications buy my books (in Indonesian) or download my free ebook (also in Indonesian).

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11 Responses to “PLC and Response Time”

  1. Certainly. If speed matters, then, we should use PLC with a fast response time, a.k.a cycle time. However, a good programming technics should be considered too.

    Chandra MDE
    http://telinks.wordpress.com

  2. yes you’re right…
    a Good PLC and Good programming techniques help us to achieve better solutions…
    btw, i like your site…. it’s nice!
    i’ll refer it in my PLC class this semester (2008) and so on…
    so my students can visit and learn from your site too…
    thanks..

  3. Wow, that’s an honour.

    I’ll post as much as I can, as soon as I can.

    :)

    Thanks.

  4. i m a student i use a project bettwin a Plc thinget and extension module but there is don’t work exactelly ,i have problem with a communication of the plc(XC32-R-E) and expansion module type XC-E4AD2DA

  5. if you can give me sollution send a me in email afefge@yahoo.fr or my skype is affa125

  6. My Article about PLC Ladder : http://plc-ladder.co.cc/

  7. It’s Good..
    Free learning PLC

    Cartiman
    http://program-plc.blogspot.com/

  8. thank u for sharing

  9. Good article sir

  10. its good thing to share, thank you.

  11. Your site is very attractive, so keep going

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