Environmental Engineering Reference
In-Depth Information
system. The manufacturer's warranties cover SHC
as a whole, including purchased component parts
applied in it. In the process of modernization of
the I&C system the entire SHC is usually replaced.
In contrast, I&C system is composed of inde-
pendently operated devices (products), obtained
in accordance with customized specification;
their mounting, connection and installation are
performed in accordance with project documents
of I&C system on operating place. Joint operation
of devices, forming a central part of I&C system,
can be inspected only on operating place, after
mounting and integration of all its components
(hardware and software). The supplier guaran-
tees apply to each product individually, but not
to all I&C system. In the process of I&C system
modernization only a part of equipment is usually
replaced (for example, many peripheral devices,
connecting cables, etc. are left).
There are significant differences in both
software SHC and I&C system. Software SHC
is its integral part and designed by the same or-
ganization as for SHC. In the process of design
of software its verification, including checking
after integration with hardware SHC, is provided.
Saving of program in read-only memory and
further checking of SHC operation are performed
on the manufacturing facility before delivery to
the customer. Downloading or modifying of pro-
grams in the process of integration of SHC with
the peripheral equipment and installation of I&C
system is often not required.
And conversely, software of I&C systems is
interpreted as a set of programs, saved in read-
only memory of SHC and all software-hardware
peripheral devices (if applicable), and also service
programs in machine-readable mediums, intended
for checking of operation of I&C system and
contained in it individual devices. These software
components are designed by different organiza-
tions at different times and independently, com-
ponent integration and further software checking
can be performed only on the operating place of
the I&C system.
Independently operated devices, being com-
ponent parts of SHC, can play different roles for
safety and can be operated in different conditions,
so the safety class, seismic category, group operat-
ing conditions and accommodation and resulting
classification requirements for resistance to exter-
nal influences, noise immunity, quality of electric
isolation, etc. can be defined for each component
parts individually, but not for SHC as a whole.
Software-hardware complexes of modern in-
dividual I&C systems can be divided into:
• One-of items, each is designed, manufac-
tured and supplied to NPPs by individual
order as a component of individual I&C
and cannot be directly (without any modii-
cations) used in other systems.
•
Replicated products, designed as compo-
nents of I&C systems important to safety
that were not of not preliminary deined,
.allowed for use at NPPs and do not require
any signiicant modiications of hardware
and/or software in the process of manufac-
turing and supply for use in diferent indus-
try branches.
Software of I&C Systems
Software is considered as one of the components
in I&C systems, starting from the time, when all-
purpose control computers were used for perfor-
mance of the main system functions. At Ukrainian
NPPs such an approach was first implemented in
information systems, developed on the basis of
serial produced computer CM-2M, which was
intended for application in automated systems,
manufactured in different industry branches.
System software, providing operation and main-
tenance, was supplied in composition of СМ-2М.
Application software, directly connected with the
tasks of process control and monitoring, was usu-
ally developed independently from the supplier
of СМ-2М.
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