AB PLC Problem

Hi,
I have two micro logix 1400 PLC connected with two Wientek HMI.
HMI configure lot of timers. In last week I found both PLC go to stop mode with negative preset value(-32767). HMI have timer limit 0-99s. This happen two time in a week with different timers. Let me know reasons. Is it possible operator put the wrong value from HMI?

There might be a problem with a timer preset of 0, change the minn preset to 1, or change the timer to .01 second timer, let the operator enter from 0 to 99 seconds, do some quick math (multiply by 100 & move to preset if LIM 1 to 99) OR (move 1 to preset if EQU 0).

For the HMI divide the preset by 100 to an integer to read.

This way your preset will be between 0.01 to 99.00 seconds, but the HMI will display 0-99.