title: PLC Ladder Logic
body: <p>I am trying to use PLC's to monitor a race track. I will be using 3 Photo sensors to show which car crossed the finish line first. Each sensor will have be OTL (Latched) instruction. Each lane will have a  light to indicate which car was in first place. The car not in first lights will not come. There will be 3 judges. At the completionof each race, once the winner has been recorded, the 3 judges will use their respective switches to reset the indicator lamps to an off state (Unlatched) in preparation for the next race.To inhibit any attempt at cheating by the race judges , the judges switches are programmed so that all 3 judges must agree to reset and a reset can only occur after all 3 cars have passed the finish line. The judges will be programmed with a One Shot Rising (OSR) instruction. It sh.ould be noted that we're working with a SLC 500 PLC. I fail to mention that Iam using Rockwell Automation software RS Logics, so please use Rockwell's instructions on your ladder logic. </p>