Logix 3400MD Digital Positioner FCD LGENIM3404-00 – 9/09
6
Figure 1: Logix 3400
MD
Digital Positioner Schematic (air-to-open configuration)
O
O
Stem
Position
Sensor
Piezo Valve
Output 2
Output 1
Hall Effect
Sensor
Flame
Arrestor
Exhaust
Spool Valve
Flame
Arrestor
Pressure
Sensor Board
Air Supply
Main PCB
Regulator
Filter
Flame
Arrestor
Digital Position Algorithm
LED
Display
FF Input Signal
Figure 2: System Positioning Algorithm
Sensor
-
+
+
+
+
Summer
Integration
I
Offset
Loop
Inner
+
-
Gmult
Pmin
Pmax
Deviation
F
OUNDATION
Fieldbus
Signal
Command In
(AO Block)
F
OUNDATION
Fieldbus
Transducer
Block
CONTROL
COMMAND
Output
D/A
Percentage
Algorithm
Control
Supply
Air
Control
Spool
Loop
Inner
ATO
Tubed
Sensor
Position
Stem
Voltage
Valve
Piezo
MPC
Soft Limits
Characterization
Linear Mode
Output
Inner-Loop