Hach Ultrapure pH/ORP Manual De Usuario página 15

To see both actual and reference sensor impedance readings:
1. Push the menu key and select SENSOR SETUP>[Select Sensor]>DIAG/TEST>SENSOR
SIGNAL.
Troubleshooting
Intermittent data
During calibration, data is not sent to the datalog which will result in the datalog having areas where
the data is intermittent.
Test the pH sensor
Two pH buffers and a multimeter are required.
1. Put the sensor in a pH 7 buffer solution and wait for the temperature of the sensor and buffer to
reach room temperature.
2. Disconnect the red and white wires from the module.
3. Measure the resistance between the red and white wires to verify the operation of the
temperature element. For a PT1000 temperature element, the resistance should be between
1090 and 1105 ohms at approximately 25 ºC. For a PT100 temperature element, the resistance
should be approximately 109 ohms at approximately 25 ºC. If the temperature element is good,
reconnect the wires to the module.
4. Push the menu key and select SENSOR SETUP>[Select Sensor]>DIAG/TEST>SENSOR
SIGNAL . For a standard pH electrode, the reading should be between –50 and +50 mV.
5. Rinse the sensor with water and put it in a pH 4 or pH 10 buffer solution (use only a pH 4 buffer
solution for antimony sensors). Wait for the temperature of the sensor and buffer to reach room
temperature.
6. Compare the mV reading in the pH 4 or 10 buffer to the reading in the pH 7 buffer. For a standard
pH electrode, the reading should differ by approximately 160 mV. If the difference is less than
160 mV, call technical support.
Sensor diagnostic and test menu
The sensor diagnostic and test menu shows current and historical information about the instrument.
Refer to Table 3.
To access the sensor diagnostic and test menu, push the menu key and select SENSOR
SETUP>[Select Sensor]>DIAG/TEST.
Option
MODULE INFORMATION
SENSOR INFORMATION
CAL DAYS
CAL HISTORY
RESET CAL HISTORY
Table 3 Sensor DIAG/TEST menu
Description
Shows information about the sensor module.
Shows the name and serial number that was entered
by the user.
Shows the number of days since the last calibration.
Shows a list of all calibrations by date/time stamp. Use
the arrows keys to select a calibration and push enter
to view the details.
Resets the calibration history for the sensor (requires
service-level passcode). All previous calibration data is
lost.
English 15