American Magnetics 187 Self-Compensating Liquid Level Controller - Manual (Page 25)

14
Operation
Operational Guidelines
3.1.2 Selecting the Appropriate Units
Repeatedly press the 81,76 key to cycle between display units of percent,
inches, or centimeters. The level reading displays the sensor length, or
percentage of the measured span, above the zero offset that is immersed in
liquid (see diagram below).
The selected units may be changed at any time except during the process
of entering a numerical value.
3.1.3 Configuring the Length Settings
The Model 187 must be configured with appropriate values for the zero
offset and measured span settings. AMI records the overall length for the
sensor on the first page of this manual as well as on the calibration label
affixed to the bottom of the Model 187 chassis. AMI has also preset the
minimum zero offset and maximum measured span to match the
purchased sensor.
The zero offset and measured span settings can be modified by the user
and are accessible by pressing the
‡/(1 key.
Note
The LEN (length) menu adjustments can only be performed in the
inches or centimeter units modes. The length adjustments are
inactive if the units are set for %, and the instrument will beep
indicating that the LEN menu cannot be entered.
MAXIMUM
MEASURED
SPAN
MINIMUM
ZERO
OFFSET
OVERALL
SENSOR
LENGTH
Overall
Sensor
Length
This is the total active region of the concentric-
tube, capacitance-based probe. This value is
recorded on the first page of this manual and on
the instrument’s calibration label.
Zero
Offset
Measured from the bottom of the probe to a
minimum of just above the liquid reference plates.
The liquid reference plates must remain
submerged at all times for proper operation.
Measured
Span
Measured from the top of the zero offset (zero
point) to a maximum of just below the vapor
reference plates. The vapor reference plates must
remain exposed at all times for proper operation.
Levels are expressed as a percentage of the
measured span submerged in liquid.