American Magnetics 286 Multi-Sensor Liquid Level Instrument (CE-Marked) - Manual (Page 39)

25
Calibration
Closed dewar calibration
value entered for C
adj
(see steps 4 and 5 of the presetting procedure)
until the current liquid level display falls below 100%, and then
continue the procedure; or 2) continue the liquid transfer until the
liquid level is determined to be 100% by means other than feedback
from the instrument and then pressing the MAX calibration push-
button.
9. Once the MAX calibration point has been successfully entered,
return to the approximate calibration factor screen, as documented
in paragraph 3.3.4.2 on page 31, and select
None from the list of
options.
10. To achieve a standard calibration of the sensor with the active
region located from the lower hole to one inch below the upper hole,
use the level data from the instrument to recalibrate the MAX point
when the percent level corresponds to one inch below the upper
hole. Use the following equation to determine the percent level at
which to reset the MAX calibration point:
where L
hole-to-hole
is the measured length from the bottom hole of the
sensor to the uppermost hole of the sensor in inches. This technique
can be used assuming the sensor was built as a standard sensor. If
the sensor was made in a custom configuration, refer to the sensor
documentation and/or drawing, or contact AMI.
Example: 20" active length sensor:
When the sensor is calibrated by the closed dewar procedure, the
actual length of calibration will be 21" (distance between the
bottom and top holes in the sensor). When the liquid is 1" below the
upper hole, the display will show 95.2% [e.g. 100%
−
(1"/21" x
100%)]. When the liquid level reaches this point during usage, push
the MAX button. The instrument and sensor are now calibrated
with a standard active region of 20". The active length setting of the
instrument should also be configured for 20".
11. Proceed to the Operation section for directions for configuring the
instrument.
MAX
percent
100 100
1
L
hole to – hole –
--------------------------------- – =