Rookie Question...HELP!

mkalavitz · Jan 23, 2006

Hello,

I am a Mechanical Engineer trying to setup my first very simple Ladder Logic program to test an item that we have here...

Here is what I am trying to do....

1. Turn master power switch on (Input 01) (toggle switch)
2. Upon master switch on I want a 2 second delay and then turn on Output 1 for 2 seconds.
3. Turn output 1 off and turn output 2 on for 2 seconds...
4. Loop back to the beginning...

As you can see this is a very basic operation...I am just tyring to oscillate ouput 1 and 2 on and off for 2 seconds each with a 2 second delay between each..

I can get it to run through the program that I have, but I am having trouble on reseting the timers that I am using...

Any direction would be greatly appreciated...
thx
Mike

geniusintraining · Jan 23, 2006

Post what you have so far,

mkalavitz · Jan 23, 2006

Here it is....

Here is what I have so far...Please see attachment...Don't laugh to hard

Thanks for the review...
Mike

geniusintraining · Jan 23, 2006

Mike,

You need something to start and stop, are you only going to use the one input?, if so you need to create a latch, what brand of plc are you using?...the way you have it wrote, after you turn the switch on it in 2 sec. all will go out puts will go high, is that what you see also ?

geniusintraining · Jan 23, 2006

Is there 4 or 2 outputs? 2 raise and 2 lowers?

Ken Moore · Jan 23, 2006

What make/model of PLC are you using?

For something this simple, you could use one of the "smart" relays.

mkalavitz · Jan 23, 2006

yes...

Yes...right now it goes through the program like this..

1. I click the master switch on...

2. There is a 2 second delay.

3. Output 1 comes on for 2 seconds.

4. Output 1 goes off for 2 seconds.

5. Output 2 goes on for 2 seconds.

6. Output 2 goes off.

I am using a little Idec Micro3 PLC...Yes...I seem to agree that there needs to be a latch somewhere some how...Have never done this before....I think I am dangerous

thx

Mike

stasis · Jan 23, 2006

there is currently no way in your program to 'loop back' to the first function. As posted, both the raise & lower timers will begin timing (timers 1 & 3). Once timed out, then both the coils will be logically true. You need to interlock the rungs so that this can't happen. Your problem could be solved in three or four rungs.

Offhand, what type of PLC are you using?

stasis · Jan 23, 2006

geniusintraining said:
Mike,

You need something to start and stop, are you only going to use the one input?, if so you need to create a latch..

as he stated he was using a toggle switch (not a PB), a latch isn't needed. The input will be true as long as the switch is flipped.

Click to expand...

geniusintraining · Jan 23, 2006

Ken is right, you don't really need a PLC unless it's already in place, try using your timer DN bit to set the other timer but use the same timer but the TT (timer timing), I am not sure on that PLC what the correct terminology would be, the point is try looking at using less... its better that way, one timer can do both, are there 4 outputs or 2 ?

mkalavitz · Jan 23, 2006

Just two outputs...

Yes...I flip the System toggle switch once to the on position...From there I want it to loop through turning output 1 and output 2 on and off....

Flip toggle on...
2 seconds delay..
Output 1 goes high...
2 seconds delay...
Output 1 goes low..
2 seconds delay...
output 2 goes high...
2 second delay...
Output 2 goes low...
Loop back to the first delay...(assuming toggle switch is still "on")

I am using a simple little block style Idec PLC...Micro3

I am on the edge of this...hmmm
thx
Mike

stasis · Jan 23, 2006

this is done using the RS500 starter, but should be close to what you need....if I understand you correctly...of course, someone will point out something wrong!

mkalavitz · Jan 23, 2006

Thanks...

I will give this a look when I get back to my home office...Thanks so much for all your help...I will let you know just as soon as I can give it a shot..
thx
Mike

geniusintraining · Jan 23, 2006

stasis said:
of course, someone will point out something wrong!

stasis,

Now come on, no one here would do would do such a thing, we all know that if the you get a output when you want it then that's all that counts:wish:

We never disagree

but now that you brought it up... here is another way

Ken Moore · Jan 23, 2006

I've never used the Idec bricks, but I assume they have a limited instruction set. Here's the code for a pico controller that does what you specified, maybe it will get you started in the right direction. Each timer is a two second on delay timer.

Rookie Question...HELP!

mkalavitz

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geniusintraining

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mkalavitz

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geniusintraining

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geniusintraining

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Ken Moore

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mkalavitz

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stasis

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stasis

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geniusintraining

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mkalavitz

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mkalavitz

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Ken Moore

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