Calibration Or Slope No Endpoint - Siemens RAPIDLAB 248 Operator's Manual

Page 4-2
Calibration or Slope Drift
pH Sensor
Sensor needs deproteinizing/conditioning
Bubbles in fill solution, or insufficient or concentrated fill solution
The problem may also be caused by the reference sensor.
pCO
Sensor needs deproteinizing
Sensor failure (confirm by measurement block routine, Page 4-10)
System
Dampness around the sensors
See Pages 3-17 and 3-19.
Partial blockage in sensors
Gas pressure incorrect/gas flow rate incorrect/leaks in gas system/gas
cylinders connected incorrectly
See Page 3-10.
Incorrect gas values entered
Barometric pressure incorrect or changed

Calibration or Slope no Endpoint

All calibrations and sample measurements must be carried out with the
front cover lowered.
Reference Sensor (pH no endpoint)
Bubble in reference sensor
Nafion inner is dry due to a large bubble, or not screwed down properly,
or poorly fitting
Sensor is clogged with crystals caused by poor filling, or bubbles
creating crystal growth
Vent hole blocked
Failed membrane
See Page 3-19.
Deproteinize/condition sensor, Page 3-7.
Debubble sensor, or empty and refill, Page 3-17.
/pO Sensor
2 2
Deproteinize sensor, Page 3-7.
Replace sensor.
Dry off measurement block and sensors.
Check sensor 'O' ring seals and replace if necessary.
Check sensors are seated properly, and the tensioner is pushed
firmly home.
Clear blockage, Page 3-31.
Check gas pressure and flow rate/cure leaks/check gases connected
correctly (cal to cal, slope to slope).
Enter correct values, Page 5-2.
Enter correct barometric pressure, Page 2-9.
De-bubble reference sensor.
Place Nafion inner if dry, or refit correctly.
Empty sensor cassette and refill carefully with reference sensor fill solution.
Unblock the vent hole in the reservoir cap.
Replace sensor cassette.
248 Operator's Manual