Troubleshooting Calibration Problems - Emerson Clarity II Instruction Manual

MODEL CLARITY II

8.3 TROUBLESHOOTING CALIBRATION PROBLEMS

Once the user has completed the calibration sequence, the analyzer verifies that the calibration meets certain
requirements. If the calibration is valid, the analyzer displays the calibration complete screen and updates the cal-
ibration. If the calibration does not meet requirements, the calibration error screen appears. The analyzer retains
the original calibration.
8.3.1 Calibration Error-User-Prepared Standard (Section 6.2)
A. For best results calibrate using freshly prepared 20.0 NTU standard. Use the procedure in Section 6.3.2.
B. Has the stock 4000 NTU standard exceeded its expiration date?
C. Is the turbidity of the dilution water less than 0.5 NTU? If you are using bottled distilled or deionized water,
open a fresh bottle and repeat the calibration.
D. Are the lamp and detector windows clean? See Section 7.2.1.
E. Is the sensor securely seated in calibration cup with no light leaking in? Putting a dark cloth over the sensor
and calibration cup and removing it should have no effect on the reading. Are both the lamp and photodiode
windows completely submerged in the standard?
F. Was the correct turbidity value entered in the analyzer?
8.3.2 Calibration Error-Commercial Standard (Section 6.3)
A. For best results calibrate using 20.0 NTU standard.
B. Has the calibration standard exceeded its expiration date?
C. Are the lamp and detector windows clean? See Section 7.2.1.
D. Is the sensor is securely seated in calibration cup with no light leaking in? Putting a dark cloth over the sen-
sor and calibration cup and removing it should have no effect on the reading. Are both the lamp and photodi-
ode windows completely submerged in the standard?
E. Was the correct turbidity value entered in the analyzer?
8.3.3 Calibration Error-Grab Sample (Section 6.4)
A. Was the referee instrument used to measure the grab sample properly calibrated?
B. Was the process turbidity reading stable when the grab sample was taken? Do not attempt a grab sample cal-
ibration when turbidity readings are rapidly changing.
C. Is the sensor securely seated in the measuring chamber with no light leaking in? Putting a dark cloth over the
sensor and measuring chamber and removing it should have no effect on the reading.
D. Is the sensor clean? See Section 7.2.1.
E. Was the correct turbidity value entered in the analyzer?
Calibration method
User-prepared standard (Section 6.2)
Commercial standard (Section 6.3)
Grab sample (Section 6.4)
TROUBLESHOOTING
Section
8.3.1
8.3.2
8.3.3
SECTION 8.0
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