gefran ILI Series Original Operating Instructions page 31

• Sensor calibration test (Proof Test)
The purpose of the test is to verify the correctness of the transduction curve of the sensor.
It is carried out by applying known pressure points to the transducer and checking the values reported by the probe.
Periodicity: every two years
• For each new installation or re-installation use anti-seize paste on the thread of the stem.
9.4. Mean Time to Restoration
The MTTR (mean time of restoration) is calculated considering travel time, device location, maintenance contracts, environmental
restrictions, warehouses and the technical time of replacement of the device (not its repairing).
In particular in the MTTR is included:
• The time required to replace and reset the device
• Travel time and any maintenance contracts
• The time to detect the failure (considered negligible in respect to the previous ones)
The MTTR calculation does NOT include:
• Any administrative delays on the part of the end user
• The unavailability of spare parts
Under these conditions the MTTR will be equal to 5 working days.
Considering instead only the technical time for replacement and restoration of the device (i.e. the spare part is already available from
the user) the MTTR is equal to approx. 4h
9.5. Indication on response times
The response time to pressure transduction is 4 ms (Analog Out response).
The response time of relay version is 250 ms.
These response times are measured considering the value of Damping Filter value set to 0s (see par. 7.4 index 0x120 and par 7.9 for
setting and limitations)
9.6. Effects on the safety function of deviations in performance
The limit of acceptability in deviations of metrological performance in order not to induce loss of the safety function is ± 5 % of the
value of span at room temperature.
9.7. Inhibition and suspension of the safety function
With the ILI SIL 2 / PL d series sensors, it is not possible to bypass the safety function of transducer.
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