Instruction Manual
D200129X012
2506/2516 Receiver/Controller
June 2017
17
9. The output pressure should be 1 bar (15 psig) for a 0.2 to 1 bar (3 to 15 psig) or 2 bar (30 psig) for a 0.4 to 2 bar (6 to
30 psig) receiver/controller. If output pressure is within application tolerance, proceed to step 12. If not, continue
with step 10.
10. If the output pressure span is narrow, move the nozzle slightly to the left or, if the output pressure span is too wide,
move it to the right and repeat steps 4 and 6 through 10.
11. Repeat the steps until the receiver/controller is within application requirements.
12. Reconnect the receiver/controller to the control loop and see the Adjustment section.
Principle of Operation
The 2506/2516 uses a basic pressure balance relay system. The relay is connected so that supply pressure is fed to the
inlet side of the relay valve and the fixed restriction. From this restriction, the air pressure bleeds into the relay
chamber on one side of the large diaphragm and also to the nozzle. As long as there is no pressure change on either
diaphragm, the relay valve remains in equilibrium with both inlet and exhaust ends closed. The area ratio of the large
diaphragm to the small diaphragm is 3 to 1. A 12 psi pressure change on the small diaphragm is balanced by a 4 psi
change in the large diaphragm.
The following descriptions show how the relay works with the standard proportional, proportional‐plus‐reset, and
proportional‐plus‐reset with anti‐reset windup receiver/controllers.
2506 Receiver/Controllers
See figure 12.
Figure 12. Fisher 2506 Direct Action Receiver / Controller Schematic
BD2388‐F
A3849
TRANSMITTER INPUT
REVERSING SWITCH
BELLOWS VENT OR REMOTE SETPOINT CONNECTION
PROPORTIONAL BELLOWS
NOZZLE
SENSING BELLOWS
BEAM/FLAPPER
ASSEMBLY
VENT
RELAY INNER
VALVE
RESTRICTION
SUPPLY
OUTPUT PRESSURE TO
CONTROL VALVE
SUPPLY PRESSURE
RELAY LOADING PRESSURE
OUTPUT PRESSURE
TRANSMITTER INPUT
RELAY BLEED PRESSURE
PROPORTIONAL PRESSURE
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