4.5 Principles of Operation
4.5 Principles of Operation
4.5 Principles of Operation
4.5 Principles of Operation
· The Displacer(Fig3. – ITEM 33)'s buoyancy is transmitted to the Torsion Bar(Fig.2 - ITEM 9)
through the Operating Rod Assembly(Fig2. – ITEM 8) then converted to electrical signals by the
compressive force or tensile force of the Load Cell connected to the bar fixture. The Wheatstone
Bridge Circuit of this load cell is consisted of a thermometer and 4 thin metallic strain gauges. The
voltages generated from the Load Cell is converted into 4~20
Ꮄ
output signals of 2 wires by an
amplifier device.
4.5
4.5
4.5
4.5.1 Principles of
.1 Principles of
.1 Principles of
.1 Principles of M
M
M
Measuring
easuring
easuring
easuring
· According to the Archimedes' Principle which states that the buoyant force on a submerged
object is equal to the fluid displaced, the submerged displacer of which the shape is cylinder is
used for measuring the level and the density of a fluid and the interface levels between two
different liquids.
· The buoyancy changes in proportion to the changes of a level and this is converted to
measuring values. The displacer needs to be completely submerged for measuring the density or
the interface level.
· The following shows the general formula for calculating the buoyancy applied to the displacer.
4.5
4.5
4.5
4.5.2 B
.2 B
.2 B
.2 Block
lock
lock
lock D
D
D
Diagram
iagram
iagram
iagram
Signal
Proportional
To
Buoyancy
Force
Sensor
Calibration
Damping
Zero
Calibration
Smart
Smoothing
Characteristic
PV
Customized
Calibration
Damping Factor
Linear, Square- root
Extracted or Customized
Physical
Unit
Measuring
Span
Transfer
Function
Physical Unit
Setpoint
Linear, Square- root
Extracted
Measuring
Span
PV
Low Flow
Out Off
mA
Substitute
Value
mA
mA
Display
On/ Off
Failsafe
Selection
PV
mA
%
Digital
Output
PV
Analog
Output
AA
7DEOH
