I do not know what functions are available in your PLC but you should be able to count an internal "tick" into a counter to time your process. Use a 1 second or 0.2 second pulse on a diff up relay into the counter. When the process completes, use a diff up again to move the data to a secure register and then use the same diff up to move 0000 into the counter. The pulse you use will depend on the process time.
If the PLC has a word shift command, you could move the timed data into the first word of the shift register and then pulse the shift register to move the data down the line.
I am used to Omron PLCs and this is a pretty standard instruction with them. You can specify your shift register starting word and how many words you wish to use. When the shift register is full, tha data in the last word is discarded on the next shift.
At the same time, you can use a second word shift register to store the time of day from the real time clock. This can then be matched up with the first word shift. Even more sophisticated method would be to run several shift registers to store day, week, month, even year if you wish.
beerchug
