User Manual
Table Of Contents
- 1 Overview
- 2 Safety
- 3 Commissioning
- 4 Operation
- 4.1 Switching on the meter
- 4.2 Login with a user name
- 4.3 General operating principles
- 4.4 Sensor-independent settings
- 4.5 Sensor info
- 4.6 Channel display
- 4.7 pH value
- 4.7.1 General information
- 4.7.2 Measuring the pH value
- 4.7.3 Settings for pH measurements
- 4.7.4 pH calibration
- 4.7.5 Calibration interval
- 4.7.6 Carrying out an automatic calibration (AutoCal)
- 4.7.7 Carrying out a manual calibration (ConCal)
- 4.7.8 Displaying calibration records
- 4.7.9 Continuous measurement control (CMC function)
- 4.7.10 QSC function (sensor quality control)
- 4.8 ORP voltage
- 4.9 Dissolved oxygen
- 4.10 Conductivity
- 4.11 Data storage
- 4.12 Transmitting data (USB interfaces)
- 4.12.1 Outputting current measurement data
- 4.12.2 Transmitting data (to a PC)
- 4.12.3 Connecting the PC / USB-B interface (USB Device)
- 4.12.4 Options for data transmission to a PC (USB-B interface)
- 4.12.5 Connecting the USB memory device / USB-A interface (USB Host)
- 4.12.6 Data transmission to a USB memory device (USB-A interface)
- 4.13 Reset
- 5 Maintenance, cleaning, disposal
- 6 What to do if...
- 7 Technical data
- 8 Lists
- 9 Appendix: Firmware update

Operation Multi 3430
74
ba75865e11 02/2011
4.9.5 D.O. calibration
Why calibrate? D.O. sensors age. This changes the slope of the D.O. sensor. Calibra-
tion determines the current slope of the sensor and stores this value in
the instrument.
Note
The FDO
®
925 D.O. sensor ages so little it does not have to be regu-
larly calibrated.
To detect changes of the sensor as early as possible, the FDO
®
Check
procedure can be useful (see section 4.9.4).
When to calibrate? z If your evaluation of the FDO
®
Check procedure suggests a calibra-
tion
z When the calibration interval has expired
z If your accuracy requirements are especially high
z Routinely within the scope of company quality assurance measures.
Calibration procedures Calibration in water vapor-saturated air.
To calibrate the FDO
®
925 sensor, use the check and storage vessel,
FDO
®
Check.
Stability control
(AutoRead)
In calibration, the Stability control function (AutoRead) is automatically
activated.
Display calibration data
and output to interface
You can have the data of the last calibration displayed (see section
4.10.6). Subsequently, you can transmit the displayed calibration data
to the interface, e. g. to a PC, with the <PRT> key.
Note
The calibration record is automatically transmitted to the interface after
calibrating.
Sample record
Calibration evaluation After the calibration, the meter automatically evaluates the current sta-
tus of the calibration. The evaluation appears on the display and in the
calibration record.
Multi 3430
Ser. no. 10139695
CALIBRATION Ox
Calibration date 30.03.2010 16:13:33
FDO 925
Ser. no. 10146858
SC-FDO 925 10158765
Relative slope 0.98
Sensor +++