Alan Bradley timers

With Mitsubishi I can use a D file to both read to and from a timer. I have tried to do same with Alan Bradley but I can read timer with ACC and put in data registor N7etc but can't seem to do it in reverse. Only way I can find is to make pulses with timer and count the pulses. Is it possible to enter N7:0 etc into timer like I enter [T1 D0] in Mitsubishi? I can't do it directly but maybe there is another way? Using a 1747-L514 5/01 CPU - 4K Mem thought I would go to Uni and learn proper way to do things but not impressed.

Hello Eric,

If I am understanding you...use a MOV to load the Pre of the timer



In this example I am loading the value of n7:1 to the preset of timer T4:1, is this what you are trying to do?

EDIT: BTW, I will be going to Mitsubishi school in Feb., then I may understand what you are talking about

Thanks thought there must be a way. I was reading what people thought were the best PLC's and I thought the best is the one "I" know. When I started at Uni I hated Alan Bradley but now I'm getting use to it I am starting to like it.

Anyway thanks again I'm sure that will work fine.

All best Eric

The timer structures in the SLC 500 and Micrologix have fixed locations for the preset (PRE) and the accumulated (ACC) time relative to their control bits. When setting up the timer you specify a preset amount. But you can, at runtime, as geniusintraining suggested, MOV other values into the preset.

But you cannot set an 'N' register as the location of the preset. One way is not the PROPER way to do a timer. It's all up to the PLC designers. But, as in most cases with a sufficiently flexible language, you can do anything with anything.

dont move negative values to timer elements it will create major fault in the contoller

bernie_carlton said:

But you can, at runtime, as geniusintraining suggested, MOV other values into the preset.

Click to expand...

You can also move values into the ACC, for whatever reason. I have processes that I control that do this in order to "skip ahead", "skip back", or reset. Works fine.

Moving zero into the ACC is ABOUT the same as a reset. The only difference may be the status of the "done" bit. For example, if the timer is timed out, moving zero into the ACC probably does not reset the done bit to zero. (Someone else can confirm this.)