A PLC controls a pneumatic cylinder. The sequence stops mid-cycle. The technician forces the output bit ON in the PLC software, and the cylinder moves. What does this confirm?
Answers
AThe solenoid valve is mechanically stuck
BThe PLC processor has crashed
CThe PLC output card has failed completely
DThe field wiring, output card, and solenoid valve are functioning, so the issue is in the logic conditions (inputs)
Correct answer: D — The field wiring, output card, and solenoid valve are functioning, so the issue is in the logic conditions (inputs)
By forcing the output and observing field movement, the tech proves the hardware path from the PLC to the actuator is intact. The logic is failing to turn the bit on naturally.
MIFOTRA exam practicealigned to CompTIA (General IT) / BICSI·4 marks·Hard