At the start of the PLC scan the:
A)status of all inputs are read.
B)status of all outputs are updated.
C)program is executed.
D)diagnostics and communications tasks are executed.

Question

Quizplus · Accepted Answer

At the start of the PLC scan, the status of all inputs are read. This is necessary in order to determine the current state of the system and to begin processing the logic of the program. The status of all outputs are updated later in the scan, after the program has been executed based on the input states. Diagnostics and communications tasks may also be executed during the scan, but these occur after the input status has been read.

At the Start of the PLC Scan The