Fluke RUSKA 7252, User Manual

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Maintenance
Calibration
6
6-9
Vacuum Sensor Calibration — Optional Case Reference Sensor
A span correction can be applied to the vacuum sensor. This correction is done using the
Calibrator software and can be performed without removing the vacuum sensor from the
Calibrator chassis.
1.
Place the Calibrator in Measure mode. Remove all pressure sources from the system.
2. The Vacuum sensors are located inside the black sensor oven assembly. Connect a
pressure standard physically as close to the vacuum sensor as possible. You may
wish to remove the top cover of the instrument and connect directly to the pressure
ports going into the quartz sensor oven assembly.
Note
On the RUSKA 7252 each sensor will have its own independent vacuum
sensor.
3. If desired, change the Calibrator’s units of measure (see Chapter 4) to match those of
the calibration standard.
4. To access the Calibration screen, from the Main Menu, select [ MENU] MENU |
CALIBRATE .
5. Select the atmospheric sensor by pressing the Sensor [ F6 ] key until the words
Vacuum Sensor A (or B) is displayed above the calibration coefficients.
6. To begin the calibration process, press CALIBRATE . If the calibration access code
is enabled, enter it at the prompt. The first calibration screen will appear.
You will use the calibration standard to apply the two vacuum points on the
vacuum sensor. The Actual value will be highlighted. This is your first pressure point in
the calibration procedure. This calibration requires the generation of two pressures within
the range of 50 to 350 mtorr absolute. The selected pressures should be spaced as far
apart as possible within the allowable range.
7.
Generate the first pressure. Enter the actual value of the applied pressure generated
by the standard and press ENTER .
8. Generate the second pressure. Enter the actual value of the applied pressure generated
by the standard and press ENTER .
9. The Vacuum sensor is now linearly compensated. Once the calibration procedure is
complete, the user should verify several pressure readings against the pressure
standard. If there are variances beyond the stated precision, then an error was
probably made in generating one of the calibration pressures, and the calibration
procedure should be repeated.
10. If the instrument is fitted with two vacuum sensor, calibrate the second
vacuum sensor.
11. Remove the vacuum standard from the instrument
12. Reinstall the cover onto the RUSKA 7252.