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T
ROUBLESHOOTING
5-2
October 1999 Rosemount Analytical 748250-L
Model 880A Non-Dispersive Infrared Analyzer
SOURCE
Information Signal
(5 Hz capacitance change)
Detector
(Modulator)
OSCILLATOR
AMPLITUDE-MODULATED
10 MHz CARRIER
VOLTAGE
DOUBLER
HALFWAVE
RECTIFIED CARRIER
OSCILLATOR BOARD
SIGNAL BOARD
5 Hz
WITH NOISE
FILTERED OUT
BUFFER
AMPLIFIER
FULLWAVE
RECTIFIER
5 Hz
BANDPASS
FILTER
FULLWAVE
RECTIFIED 5 Hz
SIGNAL
LOWPASS
FILTER
ZERO
SUPPRESSION
DIGITAL
GAIN
X 1
X 2
X 4
X 8
REF
DIGITALLY
CONTROLLED
MUX
ADC
MICRO
TIME
CONSTANT
SOFTWARE
SPAN
DAC
DAC
LIN
SOFTWARE
ZERO
SPAN 1, 2, 3
DIGITALLY
CONTROLLED
ZERO
AMPLIFIED
UNFILTERED
5 HZ SIGNAL
Note:
If several error conditions are active simultaneously, only one error message
will take precedence in the Run Mode display. To view all error messages, press
the STATUS key.
F
IGURE
5-1. F
UNCTIONAL
B
LOCK
D
IAGRAMS
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