Plc Timer Help

HELLO EVERYONE. i HAVE A PROBLEM CAN ANYONE HELP ME. i AM NEW
IN THE PLC WORLD. i AM USING A ON DELAY TIMER AND USING THE DONE BIT TO TRIGGER A LATCH OUTPUT. I AM ALSO USING THE SAME DONE BIT TO TRIGGER ANOTHER TIMER, BUT THE DONE BIT ONLY TRIGGERS THE LATCH AND NOT THE TIMER. CAN THE DONE BIT BE ONLY USED ONCE. DO i NEED TO USE A BIT REGISTER INSTEAD. DOES THE LATCH HAVE ANYTHING TO DO WITH MY PROBLEM.

THANKS
TIELP

First, ALL CAPS IS CONSIDERED SHOUTING!

What PLC are you using? By saying you are using the Done bit I will assume you are talking about AB...

Post the ladder for faster, better response.

In the following example it works fine on a Micrologix 1500 LSP Series B

You can use a bit address an infinite number of times. That's not your problem.

For the DONE bit of one timer to drive another timer, the DONE bit must remain True for the entire duration of the second timer's timing. If it drops out (because the rung conditions of timer drop out), then the second timer will stop timing (and possiblly reset if it's an AB timer, which it sounds like.)

When the DONE bit drives the latch, by contrast, it will latch/set/write-a-one-to the bit address every scan tat the done bit is active (which may be only one scan), but unless something else unlatches/resets/writes-a-zero-to that bit address, the bit address will remain unchanged regardless of the state of the DONE bit.

Hi
Allen is correct, you can use the DN bit as many times as you wish, that nor the Latch is your problem. There are many ways to resolve your problem but without knowing what your program is and how the timers function in that program would make it dificult to give you an exact fix.
You could have the Latch instruction initiate the second timer or you could have the second timer seal itself in. If neither of these help then I suggest posting some ladder for us to view.
If you want a TON to function you must keep the rung TRUE.

Good luck
Roger

I would like to be able to get screen shots like the one you used here on the timer issue. How do you achieve that, and how could I get the same capability? I see several guys using this techinque and I like it. Thanks

Click to expand...

If the question is in any way benificital to others you should ask it here not in private.

I use Flash Screen Capture that comes with the MicroSoft HTML Help Workshop (a free d/l). Just do a search on "HTML Help Workshop" and you will find it....

Software

Thanks for your advice Mr. Thornton. I will remember the questions issue as well.