This document describes a priority control program for a PLC using ladder logic with two input signals. When input X0 turns on first, output Y0 will turn on through coil R0, while also disconnecting contact R0 so that input X1 cannot turn on output Y1. If input X1 turns on first instead, only output Y1 will turn on through coil R1, and output Y0 will remain off. The ladder logic provides priority output to whichever input signal turns on first.

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Priority Control plc ladder
diagram programming
2 input signals (X0, X1) in the first person to get the priority, and then to the
invalid. The structure of this function is the time structure.
When X0 first turned on, R0 coil is switched on, Y0 power (ON), at the same
time as the R0 normally closed contact is disconnected, X1 is also unable to
make the R1 is switched on, so no Y1 output; If the X1 is turned on, then the
Y1 is turned on and the Y0 is not output, so that the first person who is
connected to the output is the priority.
Ladder diagram Instruction list wave form