Allen-Bradley Logix5000 Reference Manual page 119

Timer and Counter Instructions (TON, TOF, RTO, TONR, TOFR, RTOR, CTU, CTD, CTUD, RES) Chapter 3
Example:
When limit_switch_1 is set, light_2 is on for 180 ms (timer_1 is timing). When
timer_1.acc reaches 180, light_2 goes off and light_3 goes on. Light_3 remains on
until the TOF instruction is disabled. If limit_switch_1 is cleared while timer_1 is
timing, light_2 goes off.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 119