Fisher 546 - Page 12

Instruction Manual
D200108X012
546 Transducer
March 2015
12
Figure 7 shows output‐time relationship curves for loading and exhausting an actuator. Exhausting times are
nominally 25 percent of the loading times.
Reverse‐acting transducers operate in a similar manner except that when the DC input signal increases, the output
pressure from the relay decreases. Conversely, a decreasing input signal increases the output pressure.
Figure 6. Transducer Schematic
FEEDBACK
BELLOWS
POLE
PIECES
COIL
ARMATURE
TORSION ROD
EXHAUST
OUTPUT
RELAY
VALVE PLUG
SUPPLY
FIXED
RESTRICTION
CENTER SPACER ASSEMBLY
EXHAUST PRESSURE
SUPPLY PRESSURE
NOZZLE PRESSURE
OUTPUT PRESSURE
NOZZLE
ARMATURE
PERMANENT
MAGNET
ZERO ADJUSTMENT
SPAN ADJUSTMENT
(MAGNETIC SHUNT)
CP4285-A
A1505-3 / IL
Figure 7. Output‐Time Relationship
LOADING
EXHAUSTING
TIME (%)
0 102030405060708090
100
0
10
20
30
40
50
60
70
80
90
100
OUTPUT
19A1361‐A
A3103 / IL
(% OF 546 OUTPUT SPAN)