Hach 1950Plus, Инструкция по эксплуатации инструмента, Страница: 125 / 188

Section 7
Page 125
UVTOCMaintenance.fm
Mirror Assembly Adjustment
Figure 50 UV Lamp Assembly with Cover Removed
7.12 Mirror Assembly Adjustment
Disconnect the power to the relays before opening the analyzer
enclosure doors and read
Electrostatic Discharge (ESD) Considerations on
page 111 .
1. Locate the 8000 Display/Controller PCB assembly (mounted on the door
of the electronics cabinet). Remove the cover.
2. Refer to Figure 51 and locate test points TP3 (0V) and TP5 (SIG IN).
3. Set up the instrument:
Using an Oscilloscope (recommended):
a. Connect the signal probe to TP5 and the ground lead to TP3.
b. Set the display to 1 volt per division.
Using a Volt meter:
a. Connect the positive lead to TP5 and the negative lead to TP3.
b. Set the volt meter to ac.
The ac signal at TP5 alternates
between 1 and 2 Hz and is
asymmetric. The asymmetry will
cause the volt meter reading to vary
continuously as much as 400 mV.
This is normal.
4. Apply carrier gas to the IR inlet at approximately 100 mL per minute. Wait
2–5 minutes before checking the signal level.
5. Using a nut driver, adjust the three hex nuts at the end of the IR cell for the
highest possible voltage level:
Oscilloscope: 5 to 7.5 volts peak–to–peak within 5% with each other
Volt meter: 1.5 to 2.3 volts
6. When you have finished, calibrate the analyzer.
1. UV Lamp (2) 2. Lamp Inverter (2)
UP
1 2