10
SIL Safety Manual
DOC.SILM.EF.EN Rev. 1
September 2018
Periodic Test and Maintenance Requirements
NOTE:
• If the test is automatic, then the Test Coverage is PTC (proof test coverage), but can
also considered as DC (diagnostic coverage).
• If the test is manual, then the Test Coverage is PTC, but cannot be considered as DC.
The procedure can be performed manually or automatically. In the following,
for both cases, the following points are listed:
• Parameters to be measured
• Instruments to be used
• Failure modes detected
• Diagnostic Coverage/Proof Test Coverage
Parameters to be measured:
The following parameters have to be measured for an effective Full Stroke Test:
• Angular position of the shaft;
• Time necessary to reach to nal position;
• Output torque (as indirect measure, by means of the of pressure measurement in the
cylinder chamber)
NOTE:
Not all parameters are needed, but the following combinations can be used:
1. Measurement of angular position as function of time
(pressure measurement is optional)
2. Measurement of cylinder chamber pressure as function of time
3. Verication of nal position achievement in the established maximum time.
Section 8: Periodic Test and Maintenance Requirements
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