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The electronic pdf versions of the documents found through http://www.dnv.com/ are the officially binding versions. Copyright Det Norske Veritas.
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DNV-OS-D202 Automation, Safety, and Telecommunication Systems |
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| Ch.2: Technical Provisions |
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| Sec.3: Additional Requirements for Computer Based Systems |
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| A: General Requirements |
Guidance note: ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
The responsible body may be the yard, a major manufacturer
or another competent body.
Guidance note: ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Some essential systems will, as required by other parts of
the standards/rules, require control from a local position
independently from remote control.
The back-up means of operation is typically achieved by provision
of a CAAP (Critical Alarm and Action Panel) interfaced directly
to the node(s).
The back-up means of operation could be provided by additional Operator
Stations, providing that they have communication to the node(s),
mutually independent from the integrated Operator Station communications.
Guidance note: ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
This does not exclude the use of such storage devices for
maintenance and back-up purposes.
| — | low battery voltage results in an alarm or visual indication detectable by routine inspections |
| — | battery can easily be replaced by crew personnel without danger of losing data |
| — | battery failure has no influence on performance as long as normal power supply is maintained. |
Guidance note: Ch.2 Sec.3 A ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
The following response times are applicable for typical EUC
on offshore units:Table A1 Typical response
times Function Typical response
times Data sampling for automatic control purposes
(fast changing parameters) 0.1 s Data sampling, indications for analogue remote
controls (fast changing parameters) 0.1 s Other indications 1 s Alarm presentations 2 s Display of fully updated screen views 2 s Display of fully updated screen views including
start of new application 5 s Automatic emergency actions 1 s Gas detector response time <10 s Fire detector response time <10 s
Ch.2 Sec.3 A
502 System start-up and system restoration after power failures
shall take place with sufficient speed to comply with the system
availability requirements for the systems. The system shall revert
to a pre-defined state providing an appropriate level of safety.
Ch.2 Sec.3 A
503 System capacities shall be sufficient to provide adequate response
times for all functions, taking the maximum load and maximum number
of simultaneous tasks under normal and abnormal conditions for the
EUC into consideration.
Guidance note: ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
As a minimum this should cover:
The operator should only have access to the application(s)
related to the operation of the functions covered by the system
according to 501, while access to other applications or installations
of such, should be prevented. Hot keys normally giving access to
other functions or program exits (Alt+Tab, Ctrl+Esc,
Alt+Esc, double-clicking in background, etc.) must be disabled.- calibration data - alarm limit modification - manual alarm blocking or inhibiting.
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