TI 5 - Timers

I need to know how the timers act in a TI 5
- there are branched rungs going into the timer. What do each of the rungs do?
- Are the timers retentive or not?

If it is like the TI's I've programmed, the bottom rung enables the timer and when it goes low, the timer resets. The top rung starts the timer timing if the bottom rung is high. You can make the timer retentive or non-retentive depending on how you program the enable (bottom rung).

Remember, this information is based on TI-545 and PM-550 PLC's that I have programmed, the TI-5 may not be the same as I have never run across one.

I've only dealt with the 505 series as well. In the 505's

The bottom rung is the enable/reset bit. It must be true for the timer to time.
On a true to false transition, the timer is reset.

The top rung is the bit that is timed.

The output rung is true when the timer is done.

The timers count down instead of up like AB or others.

PJKCO said:

I need to know how the timers act in a TI 5
- there are branched rungs going into the timer. What do each of the rungs do?
- Are the timers retentive or not?

Click to expand...

From the TI505 documentation:

The 5TI (not TI 5) must be 20-30 years old? Basically the same timer operation as was used in the 5TI was inherited in to the later 500-series and 505-series that people have answered already.

Working from my 20-30 year old memory banks, I think the timer memory was retentive during a power-off. However if the contact connected to the enable/reset input wasn't retentive then the timer could get reset back to the preset value anyway on regaining power and going back to run.

If you're designing a replacement program for a new PLC I'd start from scratch with what you want to happen rather than what you think might have happened in the past.

Regards

Ken