505 Counter/Timer problem

I'm learning how to program our 505's and have a small problem that I haven't worked out. I have a line that makes widgets. They come down the line at approximately 1 every 3.75 seconds. Input X27 pulses each time a widget goes by. I want to count 10 widgets then turn on output Y27 for 5 seconds, while the counter resets and starts counting the next 10. This seems like it should be a simple thing but I just can't get it to work. Could anyone offer an example RLL of how to do this?

Thanks
Dan

Could you post your code so that we can take a look at what you have.


Sounds like you have your requirements, just break it down into simple elements.

The time at which they come down the line does not matter. Once your counter is done, you will want to look at the done bit of the counter. You will use the reset command to reset the counter. Use a latch around for the output timer. This should help you. Also, X and Y are not AB ins and outs. I:1/0 and O:2/0 are.

There is a really nice AB simulator for training, but I cant recall its name, maybe someone can help me with that?

matt

Are you talking about an old TI 505?

505 Counter/Timer

Sorry for not being more specific, yes this is a TI/Siemens 505.

I did figure it out after posting. My biggest problem is that I have been a computer programmer for 25 years, and I'm having to understand that a RLL program does not function in quite the same logical flow as a computer program, but I'm getting it.

Here's a snap shot of my RLL for this, with comments.



If there is a better way to do this I'd be happy for someone to educate me. Sometimes things don't work the way I expect, but RLL programming is starting to sink in.

Thanks
Dan

Is Y27 ever turning on?

You may need to switch the order of the C21 and Y27 rungs.
It has been a really long time since programming a TI505, but this may be a logic scan thing.

Just a thought. Good Luck.

I've never programmed a TI505, so this is nothing but a WAG.

I assume that the lower connection to the timer and counter functions is the reset line. In the PLCs I know well, when the reset line is true, the timer or counter is reset. Your logic seems to imply that the reset action occurs when the reset line is false.

505 Timer

The timer was what was throwing me in the beginning. On the TI-505 timer the top line is "start/stop" the bottom line is "enable/reset." Both signals have to be present for the timer to run. To reset the timer you turn the "enable/reset" back off. It took me a bit to think that through.

Yes, this works correctly, Y27 turns on for the desired 5 seconds after 10 counts.

I did make one change to remove the rung for C21 to reset the counter and let C20 do it's own reset, not a big change but one rung more concise.



Thanks
Dan

I still support several 505 series plc's, your last post is typical. The TI timers and counters require a true to false transition for the reset function, which you figured out.

I recommend you down load the programming reference:
http://www2.sea.siemens.com/NR/rdonlyres/5F220BA1-5924-4BFA-A5B2-D62178CA1437/0/50581045.pdf