Instruction Manual
D102748X012
DLC3010 Digital Level Controller
Configuration
May 2018
61
Partial Calibration
Field Communicator
Configure > Calibration > Primary > Partial Calibration (2-4-1-3)
Partial Calibration operations are useful when it would take too long to establish a second data point in a single
session. There are of two types of partial calibrations: capture and trim. The 'capture zero' operation sets the input zero
reference angle to the value currently being measured. It is therefore valid only at the defined zero process condition.
Trim operations recompute either gain or zero reference angle with one observation of process data. The calibration
parameter that is NOT being trimmed is assumed to be correct.
Capture Zero
Capture Zero captures the current value of the torque tube angle as the input zero. The displacer must be loading the
torque tube, and not resting on a travel stop. The torque tube must be coupled to the DLC3010 and the coupling
access door must be closed. In Level mode, the captured angle represents zero differential buoyancy on displacer, and
must be obtained at the actual process zero condition. In Interface and Density mode, the captured angle represents
zero absolute buoyancy on displacer, and must be obtained at actual dry condition.
If the displacer is overweight and it is necessary to use the partial calibration methods, select Level mode and enter the
differential density before using ‘Capture Zero’ and ‘Trim Gain’. After the gain is correct, switch back to Density or
Interface mode, (reenter individual densities if Interface), then perform a ‘Trim Zero’ procedure to backcompute the
required zero buoyancy angle.
The Capture zero procedure prompts you to verify the instrument is coupled to torque tube, coupling access door is
closed, and the displacer is completely dry (if the PV is set to Interface Level), or the process input is at the zero level
condition (if the PV is set to Liquid Level).
Note
If the handle on the coupling access door is in the position towards the front of the transmitter, the coupling access hole is open
and the lever is “locked” (pinned in the neutral travel position). In this condition, the true “at‐rest” position of the linkage may not
be captured correctly. Moving the handle to the rear of the transmitter closes the coupling‐access hole and unlocks the lever.
The Zero Reference Angle functions as the pre‐calculation zero for the process measurement algorithm. This
procedure can be run either before or after other calibration procedures. However, the procedure returns a valid result
at only one input condition - zero buoyancy for Interface and zero differential buoyancy for Level mode.
Before calibration, use the
Configure > Manual Setup >Sensor
menu to verify that all sensor and compensation data
match the calibration conditions.
Trim Gain
Trim Gain operations recompute gain with one observation of process data.
Trim Gain trims the torque rate value to align the digital Primary Variable with the user’s observation. This calibration
assumes that sensor zero is already accurate and only a gain error exists. Actual process condition must be nonzero
and able to be measured independently. Configuration data must contain density of calibration fluid(s), displacer
volume, and driver rod length.
Before calibration, use the
Configure > Manual Setup >Sensor
menu to verify that all sensor and compensation data
match the calibration conditions.
Trim Zero
Trim Zero computes the value of the input angle required to align the digital Primary Variable with the user’s
observation of the process, and corrects the stored input zero reference, assuming that the calibration gain is
