does not have the equipment or is not qualified to
resistors. Next, check the middle value of the transducer
by applying pressure to the transducer that equals the
c a l i b r a t e transducers, send the transducer to a
middle value. Then check the transducer current output.
c a l i b r a t i o n facility. Some ships have their own
calibration laboratories. If you have a problem with a
Always refer to the manufacturer's technical manual to
pressure transducer or have to replace one, you can
get the correct values for the low, middle, and high
c o m p a r e it with a known standard by using the
s e t t i n g s of the transducer. When calibration is
calibration setup. The following paragraph describes the
completed, disconnect the calibration setup, replace the
transducer cover, and return the equipment to service.
s t e p s necessary to calibrate pressure transducers
For additional information on calibration of transducers,
commonly found on gas turbine-powered ships.
refer to Propulsion Gas Turbine Module LM2500,
M a k e sure you follow all applicable safety
Volume 2, Part 3, NAVSEA S9234-AD-MMO-050.
precautions while calibrating pressure transducers.
There are three values to check when you calibrate
Troubleshooting
transducers: low, high, and middle. To calibrate a
pressure transducer, make sure the equipment served is
If you suspect a transducer is faulty, start your
tagged out of service. Close the instrumentation valve
troubleshooting procedures by making sure the same
in the pressure line to the transducer, remove the cap,
problem exists on another console or panel. This step
and connect the hose to the instrumentation valve. (The
will help you make certain that you are not just dealing
instrumentation valve is closed by turning it fully
with a faulty meter or indicator. After you verify that the
clockwise.) Remove the cover of the transducer and
transducer is in fact faulty, you must isolate the cause of
connect the multimeter to the transducer test jack. The
the fault.
multimeter should read 4 milliamps (mA) 0.3. If
T O troubleshoot a transducer, first disconnect the
necessary, adjust the ZERO ADJUST resistor to get the
pressure transducer electrical connector and check for
proper reading. This is the low reading of the transducer.
Set the multimeter to the proper scale and apply pressure
correct input voltage 1 between pins A (+) and B (-).
to the transducer that equals the high value. If necessary,
Next, check the electrical connections and cables for
adjust the SPAN ADJUST resistor as required to get the
shorts, opens, or grounds. Check the pressure transducer
correct current output value. Recheck your first and last
according to the maintenance requirement card (MRC).
Replace the transducer if it cannot be calibrated. If all
values whenever you adjust either the ZERO or SPAN
Figure 6-7.--Pressure transducer.
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