Essay On Safety Control System

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CHAPTER 1INTRODUCTION

1.1 PROJECT DEFINITION
Advances in technology over the past decades have enabled the rapid evolution of industrial process that support an increasingly large portion of the modern society way of life. The main goal of these standards is to clarify the requirements for different applications and systems, in order to elevate their safety to an acceptable level.

A Safety Control System (SCS) consists of an engineered set of hardware and software controls which are especially used on critical process systems. A critical process system can be identified as one which, once running and an operational problem occurs, the system may need to be put into a "Safe State" to avoid adverse Safety, Health and Environmental(SH&E) consequences. Examples of critical processes have been common since the beginning of the Industrial Age. One of the more well-known critical processes is the operation of a steam boiler. Critical parts of the process would include the lighting of the burners, controlling the level of water in the drum and controlling the steam pressure.

When engineering a safety system, its safety integrity must be built in. In other words, the safety integrity of the intended system architecture has to be predicted and evaluated. IEC 61508 is the major functional safety standard that introduces the concept of the safety integrity level (SIL).

1.2 OBJECTIVES
There is a large number of industrial processes where an erroneous operation can lead to important damage to their environment, and economical losses. That is why these processes, and the machines involved, must be designed to operate safely. However, the high automation and management levels required nowadays make necessary to use electronic systems for th...

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... multiple contact relays are used, in a similar way as the failure detection for the dynamic outputs, described in the preceding section.

FIGURE 6

Ra Ra Rb

Rb Rc Rc

Critical load\

1.6 Benefits of SCS
• Safer operation
• Efficiency enhancement
• Environmental safety
• According to safety rules for industries
These are basic benefits. There may be more reliable operation of plant and reliable processes achieved.
Hence this system allows to design control systems with a high safety level as well as a big increase in maintainability. Any failure can be detected by the control system and the installation will be always in a safe state. When the system allows to identify its own failures, the corrective maintenance tasks are simplified, so the maintainability and the plant availability increase.

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