TM 55-4920-328-13
d. Assemble a test setup consisting of a hose and
appropriate connectors, to connect to the trailer air
system (right side of test trailer ). Assure the SERVICE
AIR switch is in the OFF position and the PRESSURE
REGULATOR,
both
on
the
Pneumatic
Control
assembly, 9A2, is in the "no pressure" position (ccw, no
spring load) then energize the Air Compressor. Connect
the hose assembly from the test trailer air system to the
pressure transmitter coupler on the data acquisition box.
e. Connect a dc digital voltmeter to pins B(+) and C(-)
on the transmitter, observing polarity.
f. Energize the METS electrical system as specified
in chapter 2. Preliminary Checkout Prior to Test
paragraph.
g. Energize the ENGINE DC switchlight unit (27,
figure 1-25) and the CONSOLE DC switch-light unit (30)
on services panel 4A1 (9). Allow the specified 30-
minute warmup period.
h. Vent the transmitter by inserting an open coupler,
and observe the digital voltmeter for an indication of
approximately Ov dc. If not, adjust the ZERO ADJ.
(nearest the electrical output connector).
NOTE
Allowance has been made for the
inlet pressure values specified in the
following
two
steps
to
convert
absolute pressure values to gage
pressure values.
i. Set the SERVICE AIR switch to ON, and apply
pressure to the transmitter by adjusting the regulator
and observing the SERVICE AIR pressure gage, to 110
PSIG. Observe an indication of 2.5 +0.5v dc on the
voltmeter.
j. Increase the inlet pressure to approximately 235
psig and observe an indication of approximately 5v dc
on the digital voltmeter. If not, adjust the SPAN ADJ.
(Nearest the pressure port).
k. If the zero, half scale, and full scale output of the
transmitter are approximately as specified in the
foregoing, adjustment only is required.
I. Repeat steps (a) through (k) for checkout of
pressure transmitter 11MT2, substituting connector P2
for P1 (pin identification remains the same) and
substituting 11M2 coupler for 11M1. (Refer to figure
FO-12 located in the back of this manual for electrical
circuit information.)
m. After checkout of 11MR1 and 11MT2, remove the
test equipment, deenergize the electrical system, and
restore system circuitry.
5-9. Checkout of Strain Gage Type Pressure
Transmitters 11MT3 and 11MT4.
Proceed as follows:
a. With all METS electrical systems deenergized,
disconnect connector 11P3 from the mating connector
on transmitter 11MT3.
b. Connect a jumper between 11P3-A and pin A on
transmitter 11MT3. Connect a second jumper between
11P3-B and pin B on the transmitter. (This action will
provide 28v dc excitation power to the unit.)
c. Remove the dust plug from coupler 11M3 on the
data acquisition assembly (Unit 11).
d. Utilizing the hose assembly and pressure method
used in 5-8, d, connect to 11M3 and 11M4 as required.
e. Connect A dc digital voltmeter to pins B(+) and C(-
) on the transmitter, observing polarity.
f. Energize the METS electrical system as specified
in chapter 2, Preliminary Checkout Prior to Test
paragraph.
g. Energize the ENGINE DC switchlight unit (27,
figure 1-25) and the CONSOLE DC switchlight unit (30)
on services panel 4A1 (9). Allow the specified 3-minute
warmup and stabilization period.
h. Vent the pressure transducer to atmosphere,
observe the digital voltmeter for an indication of
approximately Ov dc. If not, adjust the ZERO ADJ.
(nearest the transducer electrical output connector).
i. Apply an inlet pressure of approximately 50 psig to
the inlet pressure port of transmitter 11MT3 and observe
the digital voltmeter or an indication of approximately
2.5v dc.
j. Increase the inlet pressure to approximately 100
psig and observe an indication of approximately 5v dc
on the digital voltmeter. If not, adjust the SPAN ADJ.
(nearest the transducer pressure port).
k. If the zero, half scale, and full scale outputs of the
transmitter are approximately as specified in the
preceding steps, adjustment only is required. Refer to
TB 55-4920-328-50 for calibration and adjustment
information.
5-5
