ABB Advant Controller 450 User Manual

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Control system availability is often discussed in relation to industrial processes, power
generation systems, machines, and so on. Redundancy is one
instrument to reach high system
reliability and availability.
The advantages of such redundancy include:
• Improved personnel safety
• Less risk of machine damage
• Reduction of expensive production loss
• Less demand for shift work by highly paid, qualified maintenance personnel.
Processes and machines are seldom identical and it is often necessary to adapt the solution of
the redundancy problem to the application concerned. It may be sufficient to equip particularly
sensitive process sections or functional parts with control system redundancy. The level of
redundancy considered necessary varies and can be, for example:
• 100% availability necessary - Hot stand by
• Stop for some seconds acceptable
• Stop for some minutes acceptable
• The possibility of controlled manual stopping of the process required.
When studying an operational malfunction in a production unit, it is often found that the fault is
in a motor, a contactor, a valve, or field-mounted instrumentation. It can thus, in theory, appear
more appropriate to duplicate an important measuring sensor or valve than to duplicate the
control system, but errors in the controller have more serious consequences.
When considering whether redundancy of the control system really is the best configuration,
study the question broadly. Base the result on the construction and requirements of the process
and the total function. “A chain is no stronger than its weakest link.”
By taking into consideration the risk of malfunction when designing a specific control system,
you can obtain a high degree of availability at minimum cost.
The distribution of sensitive I/O channels to different circuit boards is a form of risk-spreading.
You can divide application programs into an independent basic function and a more advanced,
perhaps optimization, auxiliary function, dependent on sensitive measurement functions.
This means that production need not be stopped when parts, both within the control system and
externally, do not function correctly.
Other means of increasing system availability, irrespective of the configuration selected,
are maintenance resources such as spare parts and the availability of trained personnel.

ABB Advant Controller 450 Specifications

General

Brand	ABB
Model	Advant Controller 450
Category	Controller
Language	English