Baker Hughes Druck DPI 610 IS, Instruction Manual

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Copyright 2007 Baker Hughes Company.
English–DPI 610/615 IS Instruction Manual | 39
General
8. Calibration
8.1 General
The instrument is supplied by the manufacturer, complete with calibration certificate(s). A
calibration period of 12 months is recommended. The actual calibration interval depends on
instrument usage and the total measurement uncertainty acceptable for the specified application.
The DPI 610 IS and DPI 615 IS are very precise measuring instruments and the test equipment
and conditions of test must be suitable for the type of work. A Class A compensated deadweight
tester must be used. The calibration check and calibration adjustment should be carried out in a
controlled environment by a calibration technician
*
.
The manufacturer offers a comprehensive and, if required, UKAS accredited calibration service.
8.2 Calibration Check
At the chosen calibration interval, the instrument readings should be compared with a known
pressure standard.
The recommended method starts at 0, increasing in 20% steps to 100% full-scale and then
decreasing in 20% steps to 0.
Note any deviations between the instrument and the pressure standard and consider traceability
(accuracy to a National Standard).
If, after a calibration check, the results exceed the tolerance in the specification (or other suitable
performance standard), carry out a calibration adjustment.
8.3 Calibration Adjustment
If the instrument is operating correctly, only zero and full-scale calibration will vary. Any excessive
non-linearity or temperature effects indicate a fault. The instrument should be returned to a
qualified service agent.
8.4 Guide to Calibration Procedures
• Use high quality repeatable and linear pressure sources and allow adequate thermal
stabilization time before calibration (minimum 1 hour).
• Conduct the calibration in a temperature controlled and preferably, humidity controlled
environment. Recommended temperature is 21°C ± 2°C (70°F ± 4°F) .
• Use deadweight testers carefully and away from drafts.
• Review and become familiar with the whole calibration procedure before commencing the
calibration process.
• The calibration routines cannot be accessed when the instrument is in BASIC mode. Use the
TASK key to select another mode, e.g. ADVANCED before accessing the CALIBRATION
mode.
* A calibration technician must have the necessary technical knowledge, documentation, special test
equipment and tools to carry out the calibration work on this equipment.