mensor DPG 2400, Руководство по эксплуатации

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Operating Instructions DPG 2400 Series 33
Digital Pressure Gauge
DPG 2400 Series
8.3 Pressure Standard
Mensor recommends the use of appropriately accurate primary pressure standards
when calibrating this instrument. Such standards should be sufficient so that when
the techniques of the ISO
Guide to the Expression of Uncertainty in Measurement
(GUM ) are applied, the instrument meets its accuracy statements as required by ISO/
IEC 17025:2005, or other applicable standards. The same requirement applies to the
vacuum gauge used to set the zero offset on absolute calibrations. The recommended
absolute pressure level for setting the zero offset is
≥
300 millitorr.
8.4 Calibration Medium
The recommended calibration medium for instrument ranges up to 2500 psi is dry
nitrogen. Hydraulic media (water or oil for example) are recommended for ranges above
2500 psi. Hydraulic media can be used with some lower range instruments. However,
special techniques must be used in filling the connection lines and pressure port.
8.5 Calibration Process
The calibration process described below is for local operation via the instrument key-
pad. Connect the DPG 2400 sensor to be calibrated as shown in Figure 8.2, Calibration
Setup.
When the Calibration function is selected from the sensor setup screen, the password
entry screen will be displayed. Enter the 4-digit password and then press the
♦
(enter)
key. For more information on entering or changing the password, see Section 6, Local
Operation.
8.5.1 Zero Adjustment
Access the zero calibration screen as described in Section 6, Local Operation.
For a gauge sensor: Vent the DPG 2400 and adjust the display to show zero pressure
by using the arrow keys on the front panel. When zero is shown, press the
♦
(enter) key.
For an absolute sensor: Connect a vacuum source to the pressure port of the instru-
ment. Apply a vacuum to the port and maintain a viscous flow, typically 300 millitorr, or
greater. (At pressures lower than 300 mTorr, the actual pressure at any particular point in
the system becomes undeterminable.) Allow sufficient time for the applied pressure to
stabilize and adjust the measured pressure on the zero calibration screen to match the
applied pressure. Press the
♦
(enter) key to store the zero offset.
For a bi-directional sensor: Apply a negative pressure source equal to R-.