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MODEL CLARITY II
SECTION 8.0
TROUBLESHOOTING
8.5 INFORMATION SCREENS
8.5.1 Overview
Information screens provide data that can be helpful in diagnosing measurement problems. To read the infor-
mation screens, go to the main display and press . Each press will display a new information screen. Once all
the information screens have been displayed, the analyzer will show warning and fault screens. In the information
screens,
S1
means sensor 1 and
S2
means sensor 2.
8.5.2 Explanation of information screens
1.
The first line shows the sensor dark current. The dark current is the sen-
sor output in mV when the lamp or LED is turned off. For a more detailed
explanation of the importance of dark current, see Section 8.2.7. Typical
dark current signal is less than 20 mV.
The second line is the sensor slope.
Slp
means the sensor was calibrated
with a user-prepared standard (Section 6.2).
Stnd
means the sensor was
calibrated using a commercial standard (Section 6.3).
Grab
means the
sensor was calibrated against turbidity measured using a referee instru-
ment (Section 6.4). Typical sensor slope is about 10mV/NTU. As the sen-
sor ages the slope will decrease.
2.
For USEPA-compliant sensors the screen at left appears. The first line is
the output from the detector monitoring the intensity of the tungsten lamp.
As the lamp ages, the detector output drops.
The second line has two pieces of data: lamp current and detector tem-
perature.
a.
The lamp current is typically either 228 mA or 257 mA. Older lamps
(rev A) operate at 228 mA. Newer lamps (rev B) operate at 257 mA.
As a lamp ages and intensity becomes too low for the lamp drift cor-
rection to work properly, recalibrating the sensor causes the lamp cur-
rent to increase. The maximum current is 360 mA.
b.
The detector temperature is the internal temperature of the sensor.
The internal temperature is
NOT
the process temperature.
3.
For ISO-compliant sensors the screen at left appears. The first line is the
output from the detector monitoring the intensity of the LED. As the LED
ages, the detector output will drop.
The second line is the internal temperature of the sensor. The internal
temperature is
NOT
the process temperature.
4.
This screen appears only if the analyzer was configured to convert the
turbidity reading to TSS. The first line is the calculated TSS of the sample.
See Section 6.6 for more information.
The second line is the turbidity of the sample.
continued on the following page
S1 Lamp
XXX.XmV
XXXmA
XX.X C
S1 LED
XXX.XmV
Detector
XX.X C
SN TSS
XXXppm
SN
X.XXXNTU
SN Dark
XXX.XmV
Slp
XXX.XmV/NTU