Process Calibrators
Calibration
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7. The 718 Calibrator is now out of the CAL mode and into the normal mode of
operation. Carefully vent all pressure, press O to turn the calibrator off, and
disconnect all pressure fittings.
718Ex Calibration
mA Measure
1. Hold down both U and D on the 718Ex Pressure Calibrator. Press and release O.
2. The display shows CAL xxx, as long as Uand D are pressed. Where xxx is a
number, indicating the number of times the 718Ex has been through the calibration
adjustment. When Uand D are released,
PASS is displayed. The password is
required before you can enter the calibration mode. The password is 817. Enter the
most significant digit first. The password appears below
PASS. Use c to increase
the displayed number, h to decrease it. When the required digit appears, press D
to proceed to the next digit, or the password check. If the password entry was
correct, the 718Ex will go to the CAL mode. If the password is incorrect,
BAD PASS
shows on the display and then the 718Ex returns to the normal operation mode. In the
CAL mode, the 718Ex should display:
0.000 mA
in the upper display and
CAL 0 mA
on the lower line of the display.
The upper display shows an uncalibrated reading. This reading is approximately
+/- 10 % of full scale of the applied reading. When D is pressed, the calibration
value is calculated relative to this reading. The lower display indicates what function
and point is being calibrated.
3. Connect the test leads from the AUX jacks of the Fluke 5520A to the mA jacks on
the 718Ex Calibrator (black to black and red to red).
4. Set the Fluke 5520A to 0.00000 mA and press O.
5. When 0.0 mA is sourced from the 5520A the upper display indicates about
"0.000 mA". When D is pushed, the unit establishes the calibration constant for
that point and the lower display changes to "CAL 24 mA". The upper display still
reflects the applied current so it does not change until after step 6 when 24 mA is
applied."
6. Set the Fluke 5520A to 24.0000 mA.
7. The upper display reads approximately 24.000 mA. Press D on the 718Ex
Calibrator. CHEC appears on the lower display.
8. The CHEC mode allows for a quick check of the calibration constants that have just
been stored. Changes to the applied current are reflected in the display. Press D to
continue. The lower display changes to:
rAnGE
Pressure Measure
The 718Ex Pressure Calibrator has built-in temperature compensation. Instruments being
calibrated should be in a stable temperature environment for several minutes before
calibration. Calibration facilities should be maintained near 23 °C nominal.
Re-calibration (re-characterization) is performed in terms of ‘PSI’ pressure units. Inputs
using other pressure units (ie. kPa and bar) must be mathematically converted.
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