Manual Part 7

TM A-CM
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x
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Fault
Oper.
TMA1
TMA2
TMA3
TMA4
TMA5
TMA6
IOM Bus
+24V DC
TMA1
TMA2
TMA3
TMA4
TMA5
TMA6
DC/DC
Converter
Indicator
Control
TMA
Support
Measurement
Indicators
P008456B
Figure 1 TMA-C M Block Diagra m
The TMA-CM supplies up to six TMAs with 15 V DC a nd a maximum of 500 mA
to each TMA. The power output is a 15-pole D-sub conne ctor on the front of th e
TMA-CM. In general a T MA consumes 70 200 mA.
The TMAs can be individually sw itched on and off by commands from the
Distribution Switch Unit (DXU).
The current and voltage t o each TMA is measured and an alarm is generated
if the values are outside the specified range, this indicate that a TMA is not
workin g properly, the values can be changed in the Operatio n and Mainte nance
Terminal (OMT). The alarm is transmitted to the DXU on the Internal Operation
and Maintenanc e (IOM) bus.
The TMA is always used together with its connection cable and connection
plate for bias in jectors. The connection plate cont ains filt ering equipment.
An indicator on the front panel is illuminated for each TMA in operational
mode. Whether or not an indicator is illumina
ted also depends on the actual
configuration. See Chapter Radio Configurations, RBS 2106 and RBS 2206.
If th e TMA or the feeder cable short-circuits, the TMA-CM limits the curr ent to
500 mA.
The power cable t o the bias injector is supervised and an alarm is generated if
the cable is not connected. The alarm is transmitted on the IOM b us.
4 (6)
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N/LZT 720 0250 Uen R2A