PLC Advantages

PLC advantages:

• Increased Reliability

• small space requirements

• computing capabilities

• reduced costs

• ability to withstand harsh environments

• expandability

• More Flexibility

• Communications Capability

• Faster Response Time

• Easier to Troubleshoot

Increased Reliability

Once a program has been written and tested, it can be easily downloaded  to other PLCs. Since all the logic is contained in the PLC’s memory, there is no chance of making a logic wiring error

The program takes the place of much of the external wiring that would normally be required for control of a process. Hardwiring, though still required to connect field devices, is less intensive. PLCs also offer the reliability associated with solid-state components.

More Flexibility

It is easier to create and change a pro-gram in a PLC than to wire and rewire a circuit. With a PLC the relationships between the inputs and outputs are determined by the user program instead of the manner in which they are interconnected.

Original equipment manufacturers can provide system updates by simply sending out a new program. End users can modify the program in the field, or if desired, security can be provided by hardware features such as key locks and by software passwords.

Lower Cost

PLCs were originally designed to re-place relay control logic, and the cost savings have been so significant that relay control is becoming obsolete except for power applications.

Generally, if an application has more than about a half-dozen control relays, it will probably be less expensive to install a PLC.

Communications Capability

A PLC can communicate with other controllers or computer equipment to perform such functions as supervisory control, data gathering, monitoring devices and process parameters, and download and upload of programs. User program PLC All the logic is contained in the PLC’s memory.

Relationships between the inputs and outputs are determined by the user program. Contactor, Light, Solenoid are Outputs. Inputs are Pushbutton, Limit switch, Sensor.

Faster Response Time

PLCs are designed for high-speed and real-time applications. The programmable controller operates in real time, which means that an event taking place in the field will result in the execution of an operation or output.

Machines that process thousands of items per second and objects that spend only a fraction of a second in front of a sensor require the PLC’s quick-response capability.

Easier to Troubleshoot

PLCs have resident diagnostics and override functions that allow users to easily trace and correct software and hardware problems. To find and fix problems, users can display the  control program on a monitor and watch it in real time as it executes.