Timer Display: AD D0-06/C-More EA9

Hello

I'm still fairly new at PLC work, as my job requires much more than just PLC code, so I cant devote all my time to it, so please bear with me.

I have an application where the end customer will enter a desired time setpoint on a setup screen, generally 10 to 60 minutes. This timer will be triggered at the end of a process pumping cycle. When the main motor shuts off it triggers a change in pointer state that is on the enable rung of a TMRA timer. When the referenced timer times out, the system will change state again to its final idle state; where it waits for operator input to start another cycle.

I have it all written and functional, however I have issues with the display.
There is a status screen that will give a countdown value of this TMRA function and the display is being erratic. The numbers start fairly close, then actually increase in value before settling down and counting down to zero when the TMRA times out. When TMRA times out it resets itself and also drives another change in pointer state so that it will not be re-energized again until another run cycle is triggered and subsequently completed.

Here's the logic I am using:
I am using a 32 bit BCD input tag to a V1364 v-memory location to bring the user provided value. The C-More is scaling the value from minutes to tenths of a second for the TMRA preset.

The TMRA timer is reset by a rising pulse of its own output coil, or by the pump starting back up (if the user requests an immediate run).

The output countdown display of the TMRA function is obtained by taking the TMRA Preset and using the LDD function to load to the accumulator, SUBD subtracting the timer accumulated value; and then OUTD to write the result as a 32 bit BCD to a new Vmemory location, which I assigned to V1366.

Then the C-More takes V1366 and does another scaling back from the 32 bit BCD value in tenths of a second to minutes.

Like I said - it sorta works .... but if you watch the display carefully - its erratic.

If helpful I could maybe post screenshots of some of the relevant code.


suggestions ? and Thank You !


Jeff

Instead of doing all of the math, why not use the special relay (SP4 - 1-second pulse) and two counters, one for the seconds (60) and one for the minutes (60). The screen could enter the seconds and minutes required.
It would make the programming easier and eliminate scaling and math.
https://cdn.automationdirect.com/static/manuals/d006userm/dl06userm.pdf
Just a thought.
Regards,
Garry

Thanks Garry, I had called AD's tech support and the guy I got alluded to the fact that he doesn't like using timers- and suggested using counters, and initially it seemed complicated but now that I think about it....maybe much simpler.

I'll post back and let you know how it goes.

I'm guessing that at some point it's a BCD/binary mismatch. Also make sure that the following timer or accumulator V word are not being used.

Thanks to both Bernie and Garry. I had indeed checked the data types, was using the 32 bit BCD for the double V memory allocation on both the data entry and reading the output values. (Number type mismatch was my last snafu on the last project).

At any rate; Garry's suggestion was easy enough to implement and has corrected the matter.

I thank you for your assistance.