If limit_switch_7 is cleared while timer_3 is timing,.Light_3 remains until timer_3 is reset.When timer_3.acc reaches 180, light_2 goes off and light_3 goes on.When limit_switch_7 is set, light_2 is on for 180 milliseconds (timer_3 is timing).Source: Logix 5000 Controllers General Instructions Reference Instead a cumulative timer is offered such as Allen-Bradley's RTO (Retentive Timer On).įigure 1. Most PLCs have a simple TON (Timer ON delay) instruction that resets to zero if the input is turned off.
