Instruction Manual
D200124X012
2500 and 2503 Controllers/Transmitters
June 2017
20
in the direction of the arrows. To lower the level or decrease density, rotate the knob in the opposite direction. This
procedure is the same for either direct or reverse action. Tighten the knurled screw.
Note
The RAISE LEVEL dial does not reflect actual fluid level in the tank or fluid level position on the displacer.
Zero Adjustment (Transmitters Only)
To make a zero adjustment, open the transmitter cover, loosen the adjustment screw and rotate the adjustment lever
around the ZERO ADJUSTMENT dial. This adjustment sets the output pressure to correspond to a specific level on the
displacer. Tighten the knurled screw.
Proportional Band Adjustment (Except Transmitters and 2503 Controllers)
The proportional band adjustment varies the amount of process variable change required to obtain a full output
pressure change. To perform this adjustment, open the controller cover and turn the PROPORTIONAL BAND
adjustment (see figure 10). Refer to the prestartup check procedures to determine the proper setting.
Specific Gravity Adjustment (Transmitters Only)
This adjustment also varies the amount of process variable change required to obtain a full output pressure change. To
perform this adjustment, open the transmitter cover and turn the SPECIFIC GRAVITY adjustment (see figure 10). Refer
to the prestartup check procedures to determine the proper setting.
Calibration
Precalibration Requirements
The controller/transmitter can be calibrated in the field, mounted on the vessel containing the process fluid. It may
also be done in the shop, but other means of obtaining a displacement force change must be provided. There are wet
and dry methods of adapting the calibrating procedure.
Note
Contact your
for information on obtaining Simulation of Process Conditions for Calibration of Fisher Level
Controllers and Transmitters—Supplement to 249 Sensor Instruction Manuals (
).
Wet Calibration
Remove the entire controller/transmitter and sensor assembly from the vessel. For caged sensors, pour the fluid into
the cage. For cageless sensors, suspend the displacer to an appropriate depth in a fluid having a specific gravity equal
to that of the process fluid.