LOGO - timer limits

Hello everyone.

I am looking for a solution in LOGO!Soft Comfort V8.3.0. Using a 6ED1 052-1HB08-0BA1.

I am currently working on an easy project, just a few buttons and valves doing some easy cycles after pushing a button. The end user wants to adjust the ON and OFF times of the valves.

To prevent a human error in the timer values entry, i want to limit the timer values. That means the user can only adjust the times from Tmin to Tmax (min 5s, max 50s). When a lower/higher value is entered, the correspoding limit is entered instead.

Thanks for any advice.

EDIT: The values are going to be changed via the LOGO! display, no external HMI or TD.