13
If the problem remains after checking the connection between the main unit and the
sensor and after washing the glass electrode, the sample to be measured may be pH
14 or higher.
Error code
Time and voltage
display section
Calibration is not possible.
The pH value set in the calibration
mode and the standard solution pH
value are not same.
Set the same value for the calibration value and
the pH standard solution value (--> Calibration
mode) or wash the glass electrode. (-->About
the glass electrode)
The sensor probe may be
damaged.
Replace the sensor probe with a new one.
The sensor probe is not connected
to the main unit, or the connection
is faulty.
Connect the sensor probe to the main unit.
Securely lock the BNC connector in place.
The pH standard solution is
deteriorated.
Replace the pH standard solution with new
solution.
Problem
Possible cause
Action
Readings are unstable.
The sensor is not properly
contacting the sample.
Immerse the sensor probe at least 3 cm from
the tip into the sample solution.
The sample being measured is
pure water with a low electric
conductivity.
For stable pH measurement, choose samples
with an electric conductivity of approx. 100
μS/cm or more.
The temperature of the sample
largely fluctuated.
Make the sample temperature stable. The pH
values change with temperature.
Readings are abnormal
The battery have run out.
Replace with new battery. (-->Installing and
replacing battery)
The glass electrode of the sensor
probe is dirty.
Wash the glass electrode. (--> About the glass
electrode)
The glass electrode surface of the
sensor probe is dry.
Wash the glass electrode. (-->About the glass
electrode) See also "Storage".
Calibration has not been
performed.
Perform calibration before measurement.
(-->Before measuring) (-->, Calibration mode)
The sensor is not properly
contacting the sample.
Immerse the sensor probe at least 3 cm from
the tip into the sample solution.
The difference between the sample
temperature and the calibration
temperature is too large.
Perform calibration with a temperature close to
the sample temperature (preferably within
±3°C).
The voltage reading
varies.
The sensor probe is not
connected, or the connection is
faulty.
Connect the sensor probe to the main unit.
Securely lock the BNC connector in place.
The backlight cannot be
turned off.
Once the backlight is turned on, it
cannot be turned off for at least 20
seconds.
The backlight is automatically turned off after 20
seconds. Or, the backlight goes out when the
unit is turned off and on again.
RS-232C communication
is not possible.
The communication conditions or
protocols are not correct.
Check the communication conditions or
protocols. (-->About the RS-232C output)
The serial port on the computer is
not open.
Check that the serial port is open by referring to
the computer's operation manual.
Summary of Contents for 6400-00
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