TABLE OF CONTENTS In older plants, control rooms consist of control panels along many sides of the control room. Many instruments and switches are located on these panels. Behind those panels are many wires, terminal blocks, and more instruments and supplies.
Newer plants are designed with consoles, which include CRT screens and keyboards. All control is done by inputting through the keyboard and checking the results on the CRT screens. The computer CPUs and input and output devices are located in another room. In some cases, programmable logic controllers and other remote field controllers are located throughout the plant.
It is better to have the input device close to the measurement point and the output device close to the control point.
By using data highways and networking cables, much information can be sent to the main computer.
Although the process industries are moving rapidly to distributed control systems (DCS), programmable logic controllers (PLC), and personal computers (PC), conventional control panels still contain a percentage of the existing and operating control systems. Even with the advent of DCS, local control panels and racks used for motor control and other functions still follow the rules used for building and maintaining conventional panels.
When control panels are new, they look clean, neat, and functional. Unfortunately, years later, the face of the panel can look dingy and the rear of the panel can look like a bowl of spaghetti. To keep control panels looking as good as new and functioning properly, every...
