Instruction manual

NGA 2000 MLT Hardware
TEST PROCEDURE / TEST POINTS
11 - 3
Emerson Process Management GmbH & Co. OHG
Instruction Manual
90002929
07/2006
Fig. 11-3: PCB "MOP"
(partial view)
LED “red”
LED “green”
11.1.3 Chopper
Test point: PCB “MOP”
Measuring instrument: optical
Signal: red LED must be off
green LED must be blinking
Failure: red LED is on / green LED is on permanent
Possible reason: Chopper not (correct) connected to PCB “PIC” (Fig. 1-32, chopper of
channel 1+2 must be connected to P34) or PCB “DSP” (Fig. 1-33)
Chopper defective
PCB “PIC”/“DSP” not correctly connected to PCB “ICB” / defective
11.1.4 Unamplified Measuring Signal at Detector
Test point: “A” and “ ” of detector PCB “VVS” (Fig. 11-2)
Measuring instrument: Oscilloscope
Signal: max. 4 V
PP
min. 1 V
PP
Failure: incorrect values
Possible reason: Amplitude adjustment with R11 (IR measurement) or R5 (UV measurement).
Amplitude will be bigger for alteration of resistance R11/R5 to smaller
values (min. value for R11: 56 kΩ)
Failure: No signal
Possible reason: Detector not connected to PCB “PIC” (Fig. 1-32) or PCB “DSP” (Fig. 1-33)
Voltage supply absent (Item 11.1.1)
Source failure (Item 11.1.2) / Chopper failure (Item 11.1.3)
PCB “PIC”/“DSP” not correctly connected to PCB “ICB” / defective
CHOPPER / UNAMPLIFIED MEASURING SIGNAL AT DETECTOR