AMI 186, Инструкции по установке, эксплуатации и обслуживанию

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21
Calibration
Approximate Calibration
accuracy use the dielectric constant for the target liquid at the temperature and
pressure maintained in the containing vessel.
6. Once the approximate calibration factor is calculated, it can be entered into
the instrument by placing the front panel control mode rotary switch in the
SILENCE position. By using the RAISE/LOWER toggle switch and holding
it in the up or down position, you can adjust the approximate calibration factor
up or down. The display will move slowly at first and then faster. Once near
the desired value, simply release the switch momentarily and then resume
changing the factor at the slower speed. Once the desired number has been
reached, release the toggle switch.
7. Once the approximate calibration factor has been entered, momentarily press
the CAL push-button labeled as "~" (the tilde character) through the small
hole provided in the instrument front panel. When the calibration factor has
been accepted, the display will show "ddd.d" and the button can then be
released. This completes the approximate calibration procedure.
Note
The approximate calibration factor should only be entered once without
resetting the MAX and MIN calibration points.
Example: Purchased a 100" active length sensor for operation in liquid argon
at atmospheric pressure, however only liquid nitrogen is available for
calibration at a maximum depth of 30":
First, the sensor is dipped as far as possible into the liquid nitrogen and
cooled. The MIN point is then set as outlined in step 2. The MAX point is set
as outlined in step 3 while the sensor is submerged 30"
in liquid nitrogen. The
dielectric constant for liquid nitrogen is 1.454 and for liquid argon is 1.53.
Substituting all values into the approximate calibration factor equation yields:
A value of 389.1 should be entered and set as the approximate calibration
factor as outlined in steps 6 and 7. The sensor is now
approximately calibrated
for 100" active length operation in liquid argon.
8. The sensor can now be installed in the dewar containing the target liquid. The
approximate calibration can be used until an open dewar or closed dewar
calibration can be performed with the target liquid.
9. Proceed to the Operation section for directions for configuring the instrument.
Approximate Calibration Factor
1.53 1 –
1.454 1 –
----------------------
100
×
100
30
---------
389.1 = =