Which of the following is NOT an advantage of PLC over electromechanical relay?

Which of the following is NOT an advantage of PLC over electromechanical relay? Correct Answer All devices such as drum, switches, timers and counters are implemented using physical controllers.

The PLC has the following advantages over Electromechanical Relay:

1. PLCs are more reliable and faster in operation
2. They are compact and can be expanded easily
3. They require less electrical power
4. They are less expensive when compared to Hardwired systems of the same number of control functions
5. Hard-wired electromechanical relays lack flexibility.
6. PLCs have very few hardware failures when compared to electromechanical relays
7. Special functions such as time-delay actions and counters can be easily performed using PLCs

1. There is too much work required in connecting wires
2. It has fixed circuit operation
3. PLCs manufacturers offer only closed-loop architecture
4. PLC is new technology so that should require training
5. There is a limitation of working of PLCs under high temperature, vibrations conditions
6. Some PLCs turn on when power is restored and may cause an accident
7. There is a difficulty with changes or replacement
8. Need extra security equipment such as really
9. Some application that performs a single function is not efficient in the use of PLC
10. Limited usage environment high temperature and harsh vibration can disrupt electronics equipment on the PLC
11. PLC is not considered necessary when it has been applied to industrial systems that do not need to change the wiring.

​Important Points

Drum, switches, timers, and counters are implemented using PLC and they are not physically operated.