Instruction Manual

Instruction Manual
D103434X012
Calibration
November 2014
43
Calibrator—indicates who performed the calibration.
Calibration Method—indicates the method of calibration.
Calibration Descriptions
Full Calibration
Weight (Bench only)—Weight Calibration is a bench calibration where weights are used to simulate the different forces
the device sees at the minimum and maximum levels. All configuration data is needed to perform a Weight
calibration. Weights are suggested based on the current density values so that the two weights closely simulate the
minimum and maximum points the device should see, or based on water for certain setups. These are suggested
values only; you can enter other values if desired.
Note
The larger the difference in the weights, the better the calibration will be, provided that the unit is not on a mechanical stop.
Note
Ensure that the moment arm is not resting on a travel stop during the calibration process. Also, the weights tend to oscillate when
placed on arm, so allow sufficient time for this to dissipate before capturing the points.
When complete, the torque rate or gain will be correct at the calibration temperature. After finalizing the installation a
zero trim may be needed since a zero shift may take place when installing the device.
Two Point (Bench or Field)—A Two Point Calibration fully calibrates the device by observing the level/interface at two
points. The two points must be at least 5% of the displacer length apart. All instrument configuration data is needed to
perform a Two Point calibration. Use this method of calibration when the length/interface can be externally observed.
Min/Max (Bench or Field)—During the Min/Max Calibration torque rate gain and zero are computed by completely
submerging the displacer in two different fluids (one of which may be air or vapor). All instrument configuration data is
needed to perform a Min/Max calibration and must contain the correct values for displacer volume and driver rod
length.
Simple Zero/Span (Field only)— for applications with relatively constant density and temperature conditions. Two
points (separated by at least 5% of the displacer length) are captured in this calibration. Only the displacer length is
needed to perform the Simple Zero/Span procedure. This calibration does not allow the use of Temperature
Compensation.
Note
When using Simple Zero/Span the device cannot be temperature compensated for fluids or torque tube. This calibration should
only be used when the temperature and the process density do not
change, otherwise an untrimmable error will occur the farther
away your process conditions get from the calibrated conditions.
Two Point Time Delay (Field only)—the Two Point Time Delay Calibration is a two point calibration in which the two
points captured can be taken some time apart. The first point is captured and stored indefinitely until the second point
is captured. All instrument configuration data is needed to perform a Two Point calibration.