omron plc

[indra 0]

Hi, I use OMRON PLC with CX PROGRAMMER software. At the moment I have problem to make software PLC for OFF DELAY TIMER ( TOF ) Please inform me HOW TOMAKE THE OFF DELAY TIMER ( TOF ) in OMRON PLC ? because I can not find it except ON DELAY TIMER ( TON ) Regards, INDRA

[pfort 20]

Too much Allen Bradley "minded" What do you need to do that you can not do with Omron timer?

[indra 0]

I can not find the OFF DELAY TIMER ( TOF ) in OMRON, only ON DELAY TIMER ( TON ) In others PLC such as SIEMENS, there is facility for TOF and TON and I just use it directly. Do you know for this TOF in OMRON PLC ?

[lostcontrol 23]

Next question will be, how do I do a Masked Move...?

[pfort 20]

I asked you what you need to do with that timer, so i, or someone else here could have help you with a concrete example, but instead of answering you asked again the same question. Same post 5 years later!!! Edited 7 Feb 2010 by pfort

[indra 0]

I Sparky, Thank you very much for your info. I just check it out in other forum "PLCTALK", and already got anwer.

[indra 0]

Hi Pfort, Sorry for my mis understanding with your previous question. I use this OFF DELAY for application in signal prresure switch of blower that is sent to DC DRIVE to STOP machine if the contact OFF and I want to delay it, so the operator machine can stop the machine normally, without suddently stop MACINE directly, after receiving signal OFF from pressure sw. blower.

[lostcontrol 23]

What pfort was trying to point out, is just because a PLC does not have a certain instruction, does not mean that a function cannot be achieved. In the example posted above, does this look that hard to implement? This is basic logic, and is quite easily done with the slightest of effort. Would it not be correct to say, I want a device to stop a certain time after the run command is removed? Whether you use a TON/TOFF/TMIDDLE/TSTOP/TMRPLC should not make a difference....

[pfort 20]

Hi, Is this what you are looking for?

[indra 0]

HI, Yes this OFF DELAY that I am looking for. Thank you very much for your example program. INDRA

[BobB 58]

There is a function block for an off delay timer. Edited 8 Feb 2010 by BobB

[lostcontrol 23]

Well, Bob suggested a FB! Does that mean that you are slowly coming round to FB's Bob?

[BobB 58]

NOT GENERALLY!! Just thought it might be useful to this person. I will use them for floating point maths etc with ST that are much easier than in ladder. As for anything digital, too slow and painful - darn site quicker and easier in ladder. Let's not get too carried away - remember the important things, I am old and old fashioned!! I like to get things done really quickly and make money!! FBs generally are painfully slow and a pain in the 'A' - ladder is quick (keyboard) - ladder is good. Many specifications here specify ladder for everything as virtually anyone can understand it. Also when you have an electrician on the phone in the middle of the night trying to trouble shoot explaining ladder is a dang site easier than FBs. I have addmitted before that FBs for maths are really good and quick - quick is the important thing so I maximise my profits!! Edited 9 Feb 2010 by BobB

[pfort 20]

I think he is better learn timers before hear about FB. And...who would use FB instead of a simple timer?

[Sleepy Wombat 27]

I could just imagine the banter I could of hit you with on this one Bob, heh hee heh. you left that one wide open.

[BobB 58]

Banter or not Sleepy they are generally a pain in the 'A' for mine. I like things wide open by the way - one of the problems with FBs are that they are closed and while opening them for a look you miss everything else that is going on in the program!!! Must send you some pretty good funnies sent to me in the last couple of weeks.

[Berti Baker 7]

Hi BobB, What you see as the pain of FB I see as the value. If the FBs are properly designed then they SHOULDN'T interact with the rest of the program so when they are closed, you shouldn't need to know what goes on inside the 'black box', and when you're inside you should be protected against affecting the rest of the program. This is just general OO principles from general programming now filering into PLC programming - but from previous posts I know you might not be a big fan and I REALLY don't mean to offend you and start a massive debate, so I will limit it by saying "for multi-developer / large developments" that there is a place for data encapsulation with FB. Properly used they should SAVE time, money and PLC memory and most of all - make a program MORE maintainable. But they are just a tool to help - not a be-all and end-all. Regards, BB

[lostcontrol 23]

I would like to see some more information on how they save PLC memory? Most times we have used them, the memory usage is quite intense, especially with individual instances or certain FB's. There is the huge extra memory that can now be allocated, but each FB still takes up ladder memory as well..

[Berti Baker 7]

Hi, You're absolutley right that Function Blocks only SAVE memory when you reuse them. In my tests I found the payback point was between 2 and 3 uses of the FB. It depends a bit on the size of the body code, but even for quite small FBs 3 invocations uses less memory than 3 copies of the body. Not only that but it looks like the CJ2M now comes with 20K FREE Function Block memory - even the 5K version (according to http://forums.mrplc.com/index.php?act=atta...st&id=8510). Now if the Function Block memory is FREE that's even better !! Regards, BB

[lostcontrol 23]

But what about Ladder memory, FB memory is one thing, my point was about ladder memory. Every unique instance of a FB utilises its own amount of ladder memory, as well as FB memory, and depending on design, some FB's utilise quite a bit of ladder memory... I think that we need to explore better implementations of certain functions, such as timers/stored variables etc. I have an idea on how to test this, just no time just now...

[muzzamil.baig 0]

Hi, To use an off delay timer you need to use the normal timer instruction along with a reset instruction, such that when the time is completed it resets the bit which will then turn off whatever you are trying to off using the timer. I hope this helps

[Crossbow 295]

It's been 5 years I doubt they are waiting for a response...