Emerson Rosemount CCO 5500, Reference Manual

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LEDs Description
Power supply LED
+12 V This LED should be ON indicating that the power
supply unit is functioning correctly. This LED ex-
tinguishes if the supply voltage drops from 12 to
11 V.
6.5 Test points
If you need to do further checks on instrument operation, there are various test points
within the instrument. Many of these are simple DC voltages, and you may check them
using a voltmetmeter set to DC volts; if they are not DC voltages, you can investigate them
using an oscilloscope.
Control unit Description
T1 D1 signal from receiver head with some condi-
tioning in the processor, smoothed by a factor
of divide by 10. Flattened saw-tooth, 32 to 45
Hz (modulation frequency), 1 V peak to peak
(maximum), centered on 0 V. You can take 0 V
to T1 to T6 from the 0 V test point, top left of
board. Test points T1 to T6 are in the center of
the board.
T2 D1 signal after amplification in the processor.
Flattened, saw-tooth, 32 to 45 Hz, 3.5 V peak to
peak (maximum), centered on 0 V. Amplitude
may vary by a trim put. Refer to
Section 4.9.1 .
T3 D1 output to the A/D converter within the mi-
cro-processor offset by 2.5 V. Flattened saw-
tooth, 32 to 45 Hz, 3.5 V peak to peak (maxi-
mum), centered on 2.5 V.
T4 As T1 but for D2 signal.
T5 As T2 but for D2 signal.
T6 As T3 but for D2 signal.
T7 Receiver ambient temperature to the A/D con-
verter with the micro-processor - 1 mV repre-
sents 33.8 °F (1 °C).
T8 Normalizing input for pressure before A/D con-
verter 0.8 to 0.4 V = 4 to 20 mA.
T9 As T8 except oxygen.
T10 As T8 except temperature.
+5 and 0 V Supply rails for micro-processor. DC voltage.
Troubleshooting
98 Rosemount CCO 5500