3. a. PLC\'s run the program using a cycle of reading the inputs applying these
ID: 1767078 • Letter: 3
Question
3. a. PLC's run the program using a cycle of reading the inputs applying these inputs and updating the outputs. This can lead to some faults occurring i Relating to this cycle explain the possible reasons for (10 marks) intermittent faults li. Some pieces of code fail due to the order of the commands, give an example of this and again explain, relating to the above cycle, why this is. (10 marks) b. It is also possible in pneumatic circuits to produce a locked in signal. i. Explain the term locked in signal and give one example, with a diagram, of how this can be caused. (5 marks) i. Explain how such a signal can be avoided (10 marks)Explanation / Answer
a)