Environmental Engineering Reference
In-Depth Information
Table 16. Electric strength of isolation (test voltage)
Test Voltage for the Circuit with a Nominal Voltage
Test Conditions
(Temperature and Humidity)
Over 100
to 1000 V
Inclusive
Safety Class
Over 20 to 100 V
Inclusive
To 20 V Inclusive
upper working
1500 V
1500 V
2000 V
2(А)
upper limit
500 V
500 V
1200 V
upper working
100 V
500 V
2000 V
3(В)
upper limit
60 V
300 V
900 V
upper working
100 V
500 V
2000 V
3(С)
upper limit
60 V
300 V
900 V
• Not less than 40 MОhm under normal test
conditions.
• Not less than 10 МОhm under an upper
temperature working value.
• Not less than 2 МОhm under upper humid-
ity working value.
• Use of diferent data transfer paths between
redundant channels.
Independence of I&C systems, SHC and re-
dundant channels, related to 2(А) and 3(В) safety
classes, is also provided regarding all specified
for them category B functions. For category C
functions independence requirements are speci-
fied in reasoned cases on agreement between the
designer of the I&C system (developer of SHC)
and operating organization or the customer.
Normal test conditions- naturally set in a
room, where tests are executed, upper working
values of a temperature and humidity- according
to Table 2, upper limiting values - according to
Table 3 and 4.
Independence from adjacent I&C systems
,
SHC and redundant channels are provided by:
Permissible Disturbance Emission
Operating stand-alone component parts of SHC
and peripheral equipment during operation, con-
nection and disconnection do not create switching
or other disturbances, which could cause operation
failures of other components of the I&C system,
connected to the same primary power network or
to the same power source.
Level of radiated disturbances during opera-
tion, connection and disconnection of operating
stand-alone component parts of SHC and periph-
eral equipment does not exceed values specified
in CISPR, 2006 and an identical state standard
of Ukraine that regulates requirements for in-
formational technology equipment, intended for
operation in manufacturing facilities.
• A selection of a structure of connections,
interfaces and communication protocols
through communication lines or a local
network, which allow checking accuracy
of obtained data and in case of failures of
any of devices, connected to a local net-
work, - to keep a possibility of communi-
cation between other devices.
• Use of hardware and software for control
of data lows, protocol processing, detec-
tion and correction of errors in order that
any failures during transmission and recep-
tion of messages do not inluence on per-
formance of speciied functions of the I&C
system (SHC).
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