9
2850 Conductivity/Resistivity Sensor Electronics
Maintenance
Troubleshooting
The 2850 requires no periodic maintenance.
• Coatings on the electrode may cause slow response or drift.
• Clean metallic surfaces with a mild detergent and a non-abrasive brush or cotton swab.
LED and Output Condition
Possible Causes
Suggested Solutions
Current Out:
LED off, current output is 22 mA
(S
3
L) out: "Check Sensor"
• SW3 and SW4 set to all OPEN
(factory setting).
• No electrode installed.
• SW3 (and SW4) not set correctly.
• System not ready.
• Normal for new system.
• Install electrode.
• Set SW3 and SW4 correctly.
• Retry (recycle power).
During EasyCal, the LED blinks
rapidly for 4 seconds.
• Measured value of the test solution is
outside the ±10% tolerance.
• The electronics or the electrode is
defective.
• Use fresh test solutions and restart
the calibration.
• Replace the electronics or the
electrode.
After completing calibration
procedure, the output values are
inaccurate.
• Insuf
fi
cient time allowed for electrode
stabilization during calibration procedure.
• Test solutions are contaminated.
• EasyCal performed with temp comp
Inactive, then temp comp Active for
measurement. (or vice versa)
• Recalibrate and wait at least 2
minutes after placing electrode in
solution before pressing SW1.
• Use fresh test solutions and restart
the calibration.
The output of the 2850 indicates a
value that is off by a factor of 10
(e.g. 10x, 100x the correct value)
• The cell constant selection on the
2850 (SW3 or SW4) does not match
the actual input.
• Match the 2850 switch settings to
agree with the sensor being used.
