Principal Of Servo Measurement - Honeywell FlexLine SmartServo 954 Service Manual

PRINCIPAL OF SERVO MEASUREMENT

3 PRINCIPAL OF SERVO MEASUREMENT
3.1 Principle of measurement
Figure 3-1
12
Principle of measurement
The principle is based on detection of variations in the buoyancy of a
displacer. The displacer is suspended from a strong, flexible measuring
wire which is stored on a precisely grooved measuring drum.
The shaft of the drum is connected to the stepper motor via a magnetic
coupling.
The apparent weight of the displacer is measured by a force transducer.
The actual output of the force transducer is compared with a desired
value for the apparent weight of the displacer. If a discrepancy exists
between measured and desired value, an advanced software control
module adjusts the position of the stepper motor.
Service Manual
954 SmartServo FlexLine
Part No.: 4417340 Revision 1