Advantages of PLCs
1. Higher Reliability
Once the program was written and tested it can be easily downloaded into other PLC’s memory. It requires lesser and simpler wiring compared to conventional hard-wired circuits employed. Hence reliability of the system increases significantly with PLCs.
2. More Flexibility
It is easier to create a new program module or change an existing program in PLC compared to hard-wired circuitry system. These software program modules can be changed whenever required. Use can modify the programs in the field and if required, security can be enhanced by hardware interlocks such as key locks and software features such as passwords.
3. Lower Cost
PLCs were originally designed to replace relay control logic which is not economical and complex especially for large control circuits. With PLCs, the cost savings have been so significant that the relay control becomes uneconomical except for some power applications. Generally, if the application consists of more than half a dozen control relays, PLCs are least expensive to install.
4. Communication Capability
Communication capability of PLC with the other controllers and computers in the system is one of the main advantages compared to relay control circuit. Functions such as Supervisory control, data acquisition from the field, monitoring devices and process parameters associated with the field and downloading and uploading of programs can be easily possible with the PLC compared to hardwired circuits.
5. Faster Response
PLCs are designed for high speed and for the real-time applications. Response time for PLCs is much smaller compared to relay logic circuits. The programmable controllers operate in real time i.e, an event taking carrying out at the field will result in the execution of the operation of output.
6. Easy to Troubleshoot
PLCs have inbuilt diagnostics and override functions that help the user to easily trance the software and hardware errors.