Which of the following statements is NOT true during a PLC scan?
A) If the output symbol is active it turns on the output field device and then sets the corresponding bit in the output register to a one.
B) Input values are scanned first.
C) The PLC uses the value in the input register to set the conditions for input logic symbols.
D) If power flow is present in a contact, the contact is highlighted.
E) The voltage present at the input terminals determines the value of the input register.

Question

Quizplus · Accepted Answer

During a PLC (Programmable Logic Controller) scan, the process typically involves reading inputs and then executing the program logic based on those inputs before updating the outputs. The statement in A is not true because the process actually involves setting the corresponding bit in the output register first, based on the program logic, and then the output field device is turned on or off accordingly. The output register acts as a buffer between the program logic and the physical output devices.

Which of the Following Statements Is NOT True During a PLC