ABB AV2123000 Positioner User Manual

SECTION 2 - DESCRIPTION AND OPERATION
INTRODUCTION
This section describes and explains the functional and physical
operation of Type AV1 and AV2 positioners. Figure 2-1 diagrams
the operating principles of the positioners. Figure 2-2 shows the
placement of a positioner in a typical control system.
SIGNAL
DIAPHRAGM
CAM
DIAPHRAGM
FORCE
BALANCE
BEAM
GAIN
HINGE
SPRING
PILOT VALVE
TO ACTUATOR
SUPPLY PRESSURE
TO ACTUATOR
O1
S
O2
RANGE
SPRING
FORCE
INPUT
SIGNAL
PRESSURE
RANGE
SPRING
T00354A
Figure 2-1. Operation Diagram
LOAD
SET
POINT
+
–
CONTROLLER
+
–
POSITIONER ACTUATOR
+
PROCESS OUTPUT
–
POSITION
TRANSMITTER
(OPTIONAL)
LINKAGE
PROCESS FEEDBACK
T00770A
Figure 2-2. Block Diagram
INTRODUCTION
2 - 1