DH Instruments PPC2 AF - Set the User Level (Initial Start up Only); Check Proper Pressure Measurement Operation; Checking Absolute Pressure Measurement; Checking Gauge Pressure Measurement

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2. INSTALLATION AND SHORT TERM STORAGE

2.4.2 SET THE USER LEVEL (INITIAL START UP ONLY)

PPC2 AF's front panel interface provides the means to access all PPC2 AF data and

functions including functions which, if used inadvertently or incorrectly, could change critical

metrological and/or operational parameters. The USER LEVEL function (see Section 3.4.4.6)

allows these areas to be password protected. The "low" security level protects only the most

critical internal calibration data. It is recommended that this level be set on all PPC2 AF's

even if no special security precautions are desired.

2.4.3 CHECK PROPER PRESSURE MEASUREMENT

OPERATION

2.4.3.1 CHECKING ABSOLUTE PRESSURE MEASUREMENT

If the PPC2 AF is not vented, press the VENT direct pressure control key to vent

it (see Section 3.1.2.2).

Press the UNIT function key (see Section 3.2.2). Select psi and then select

absolute mode.

Using the RANGE function key to change ranges (see Section 3.2.1), observe the

current value of atmospheric pressure displayed by each range. Check that

these values agree within ± 0.2 psi (1.4 kPa). If they do not agree, PPC2 AF may

need calibration or repair.

2.4.3.2 CHECKING GAUGE PRESSURE MEASUREMENT

If the PPC2 AF is not vented, press the VENT direct pressure control key to vent

it (see Section 3.1.2.2).

Press the UNIT function key. Select psi and then select gauge mode.

Using the RANGE function key to change ranges, observe that zero psi, ± 0.01 psi

is indicated for each range within 10 seconds. If it is not, PPC2 AF may need repair.

2.4.4 LEAK CHECK

If desired, perform a leak check of the test system (see Section 3.2.8).

2.4.5 PURGE

If the SPLT is included and installed in the test line, perform a purge of the system if it may be

liquid contaminated and descending pressures will be controlled (see Section 3.2.8).

Operating the PPC2 AF connected to a system with liquid contaminants without taking

proper precautions to purge the system and test line may cause contamination of the

PPC2 AF that will require non-warranty service.