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5p6d

micrologix 1100

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I just started looking at the RSLogix Micro v 8.20.....I'm learning the software adn trying various basic things.....I need a timer...just a regular timer that starts when true and goes for T then turns off. I see only on-delay and aff delay timers.....are these the only 2 timers available in this software?? Hard to believe! mark

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Using those you can produce any time function you want. You describe an interval timer. If the enabling conditions will always be true for longer than the timer preset then simply use the 'Timing' contact (/TT) of the timer as an 'interval on' contact. If there is a possibility that the enabling conditions will go false before the timer is finished then you can go one of two ways. If. in this case, you want the condition to turn off as soon as the enabling condition goes away then just use the 'TT' bit as described. If you want the full timer time regardless then place a contact of the 'TT' bit in parallel with the enabling condition. This will be a 'latch on' for the time duration of the timer.

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There is a third "RTO" Retentive Timer On. What others do you think there should be?

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The majority of my ladder programming has been seimens LOGOSoftComfort, which has several timers that are painfully easy to understand and use, including on delay, off delay, on/off delay, retentive on delay, pulse trigger, edge trigger, asynch pulse, and some others. I have no experience with the AB software and am trying to figure out how to use the functions. I've been looking at the help file for the On delay and it sorta half explains it....the parameters seem to be time base and preset, those I understand....DN is basically the output of the thing, but what is EN used for? The rung would connect to the left side..."TT" is mentioned only as one of the 3 "instruction bits" (13=DN; 14=TT; 15=EN.....done, timing bit, enable bit) but I'm not sure how to use these 'bits'.... b_carlton made a what I'm sure is a great suggestion, but I don't know how to do that.....I will be using many timers for various reasons, on delay, time elapsed, waiting periods, etc.... Any help is extremely appreciated... thanks

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The done(DN) bit becomes active (true) when the accumulated value equals the preset. The enabled(EN) follows the rung condition. Active (true) when the rung is true. The timing(TT) bit is active (true) as long as the timer is timing. Goes false when the timer reaches its preset value. Edited by Mickey

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The DN or done is exactly as it sounds, it becomes true when the time value you enter becomes true. The TT bit becomes true when the Timer is Timing and is off both when the rung is disabled and when the timer finishes timing. I have not used the EN bit as often but if my memory server correct, it is always on as long as the rung is true, meaning the timer may not be timing any more but you do not have to repeat truth statements for a timer and for something else, you can just use this bit.

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I guess I don't see where you access the 'TT' output...the only connection points are the rung, the 'EN' and the 'DN'...

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You don't 'access' it by a line connection. The named bits exist as references and can be used anywhere as contacts, either Normally Open or Normally Closed.

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:you dont access it so to speak, you use a contact and instead of using an input address you use TT ex I:0.0/4 instead use T4:0/TT

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Use the TON function. Branch the timers TT bit around the input to keep it enabled with only a single input pulse if you need. You can then use the EN, DN, or TT bits other places in the program.

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ok, so I can just use a NO contact and refer it to the TT of, say T4:0? Man I've got a LOT to learn with this software! I appreciate the patience, I'm sure these are very rudimentary questions...

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going from one manufacturer to another can be quite confusing. I am an AB guy, in the middle of learning DirectSoft, while tring to program an Eaton processor. I feel your pain.

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I've done a little with Directsoft.....kind of annoying having to go through Directsoft5 and browsing to find your file rather than double clciking on the PRJ file....I wish they'd all get together and make one simple program...

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We've all had to go through the rudimentary parts. It was fun before there were handy Interneet Forums to help. By the way, in making transit from AB to Directsoft try my site - http://www.theplcguy.com/ABtoAD/Introduction.htm

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Oh please tell me there's a Logosoftcomfort to AB site! :)

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I suggest you download the instruction set reference manual for the Micrologix 1100 PLC from the literature library at Ab.com. Link There are graphical charts in the manual for each of the timing instructions that show how each bit sequences on/off for the TON, TOF and RTO timers. In 26 years of PLC programming I've never encountered something that I couldn't do with those timers, including everything you mentioned.

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ok....the TT 'bit' is set when the timer is running.....sort of an accessible accumulator parameter.....TT=accumulator. So, the rung starts TT and it runs until TT=PRESET, and the output DN turns on. This (TT) would be like a regular 'time lapsed' timer..... Using DN gets you the On-delay functionality.... interesting...

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ya, I found that thing, the description of how to use the function is a little light on detail......

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Wow, thanks.....it looks like the top one would stay on for 10s if you held the input on, and the bottom one would do the same, but with a momentary input.... if you switched the bottom one's "timer 2 timing" contact from TT to DN, the light would want to come on after 10s but the input would go away at the same time so it wouldn't come on, right?

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There's a lot of capability with the three timers available. Kinda the less is more approach. From my point of view, I would hate to have to learn 10 different types of timers to get what I needed done. Frankly I rarely use the TOF. Usually throws off my clients if I do. I will say that I was surprised when I put together the vids for these three little timers and it took about an hour to go through it all. Usually an instruction can be covered in about 10 min. Give the micro a little time before you down it. Ab has done a lot of things right with that platform and especially the Logix platforms. I've used a lot of different brands and my preference is still AB.

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Oh no, I don't have any problem with it! I think it looks really cool, I just don't know how to use it yet....the fact that there are basically 2 timers that can be configured is awesome.....I rarely if ever use off-delays myself....twisted logic to me....like inverted outputs....

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Here are some examples. Hopefully this will help you begin to visualize what you can do and kick start your imagination on what else you can do. TIMEREXAMPLES.RSS

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holy cow, thank you so much! I'll check them out.....I haven't looked yet, but I assume it's possible to display message text on the screen based on circumstantial events?

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