ITPEC FE Morning April 2021 Question 20
Which of the following is the appropriate explanation of sequence control for controlling industrial devices?
Explanation
Stepping through each phase in a predefined order or set of conditions — that is sequence control.
Sequence control moves from one stage to the next when the previous stage ends or a condition is met, as in a washing machine program (fill, wash, rinse, spin) or traffic lights. It follows fixed steps rather than measuring and correcting an output.
Answer (c)
Why not others:
- •(a) — reasoning with vague degrees such as "slightly more" is fuzzy control
- •(b) — continuously measuring the controlled output and correcting deviations is feedback control
- •(d) — acting in advance on a disturbance that can be predicted is feedforward control
Key rule: Sequence control follows fixed steps, feedback control reacts to a measured deviation in the output, and feedforward control acts on a disturbance before it reaches the output.
Basic Theory · AI-written, may contain errors
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