Servomex 2223A, Руководство по функциональной безопасности

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2223A Oxygen Transmitter Functional Safety Manual
10 02223006A / Revision 0
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Measurement 1, Current 1, Measurement 2 and Current 2 should be configured to
map the input current range to the corresponding measurement range. Note that
Current 1 must be greater than zero.
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Under Range Current should be set to a value less than Current 1 that represents a
fault condition in the external measurement.
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Over Range Current should be set to a value greater than Current 2 that represents
a fault condition in the external measurement.
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Name, Filter Factor and Units should be set as appropriate.
3.5 Protection of settings
The 2223A Oxygen Transmitter is supplied with all passwords set to default values. After
configuration these should be altered to provide protection against unauthorised changes.
3.6 Checking safety
Safety checks should be carried out after installation and at regular intervals in accordance
with IEC 61508. The required interval between tests will depend on the application, the
design of the overall safety instrumented system and the target SIL. The recommended
proof test interval is a maximum of one year.
If there are any transmitter fault conditions present, these must be resolved before
proceeding. It is also recommended that any maintenance-required conditions are
addressed.
For all tests it is assumed that the 2223A Oxygen Transmitter is powered and has reached
stable operating temperature.
3.6.1 Checks where pressure compensation is not used.
1. Take appropriate action to ensure that spurious outputs will not compromise safety or
cause false trips.
2. Using the built-in analog output test feature, set the output to 0.0mA and verify that
the correct current is generated. Repeat with the output set to 20.0mA.
3. Carry out a full low and high calibration.
4. Perform a reference measurement with an oxygen concentration between the low
and high calibration points. Check the mA output current and verify that it is within
the required tolerance.
5. If an internal flow sensor is fitted, alter the flow of gas through the analyser and
check that the flow alarms are triggered at the appropriate levels.
6. Restore normal operation.