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RP6 – Liquid Level Meter Calibration (Figure 10)
Calibration is required to ensure accurate meter readings and
should be done whenever an error in level readings is suspected
or when the meter has been replaced. If a calibration procedure is
unsuccessful, the calibration value will not be saved and an error
code will be displayed on the LEDs (See Table 4). To calibrate,
first enter calibration mode before performing either full or empty
calibration.
Enter Calibration Mode
a. Press and hold the hidden calibrate button. While still hold-
ing, continue to step B.
LED 8
LED 1
Calibrate Button
(Hidden)
Operate Button
b. Within 3 sec, press and hold the operate button. LED 1 and
LED 8 will begin alternately flashing to signify that calibra-
tion mode has been entered. If an error occurs, the calibration
value will not be saved.
c. Proceed to next step within 45 seconds.
Calibrate Empty Capacitance
a. Press and hold calibrate button for 3 sec to record empty ca-
pacitance reading (LED 1 will flash for 3 sec).
b. LED 1 will flash to signify successful calibration. If an error
occurs, certain LEDs will flash, signifying a specific error code
and the calibration value will not be saved. (See Table 6 for a
list of error codes.)
Calibrate Full Capacitance
There are two full capacitance procedures available. Procedure 1
is quite accurate and quicker to perform since it does not require
you to fill the dewar. Procedure 2 is even more accurate, but re-
quires the dewar be vent-full with LOX. To start either procedure,
calibration mode must first be entered. There is no need to per-
form both procedures for any given calibration.
Procedure 1: Capacitance Simulated Full Method
a. Press the operate button 3 times within a 5 sec period of en-
tering calibration mode. One of the LEDs will light continu-
ously.
b. Press the calibrate button until the correct LED is continu-
ously lit (See Table 4).
c. Press the operate button to save the calibration. If an error
occurs, the calibration value will not be saved.
Procedure 2: Fill Method
a. Enter calibration mode on a vent full unit with properly satu-
rated LOX. If unit has just been filled, allow it to stabilize
before continuing.
Model
LED Setting
Liberator 20
LED 2
Liberator 30
LED 3
Liberator 37
LED 3
Liberator 45
LED 7
Liberator 60
LED 6
FIGURE 9:
Shroud Assembly
TABLE 4:
Capacitance Span LED Settings
NOTE: In order to obtain an accurate calibration, you must cali-
brate both empty and full capacitance. For the full capacitance
part of the calibration, you can choose either of the two proce-
dures.
FIGURE 10:
Liquid Level Meter
d. Insert new battery with the positive terminal facing up.
e. Apply a thin coating of fluorolubricant to the o-ring.
f. Replace battery cover by pushing it into the back of the level
meter’s case, ensuring the o-ring seals evenly and without kinks
to restore the air-tight seal.
NOTE: Please use only one of the following calibration methods.
WARNING:
You must first calibrate the empty side, and then cali-
brate the full side.
Liberators Technical Service Manual • PN 13350704 Rev
K
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