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4.3
Optical sensor cap
4.3.1
The sensor cap is a key part of the optical DO probe. The surface coating of the cap cannot be
scratched or mechanically worn. Otherwise, the service life of the sensor cap will be reduced or the
probe will be damaged. Please pay special attention to it when using the probe.
4.3.2
The surface coating of the sensor cap cannot withstand high temperature, so the optical DO
probe cannot be tested in water above 122˚F (50˚C).
4.3.3
If the surface of the sensor cap is contaminated, please do not use alcohol or organic solvents to
clean, otherwise it may damage the probe. It can be gently wiped with a soft clean cloth. To disinfect the
probe, immerse it in 3% hydrogen peroxide for 15 to 30 minutes and then rinse off with clean water.
4.3.4
The sensor cap has a service life of more than 8000 hours. When the probe is not being used, the
service life will not be reduced, so the actual use time of the sensor cap is far more than a year. The
major factor affecting the service life of the sensor cap is the surface coating being damaged under
external force. So, the key is to protect the sensor cap from external damage.
4.3.5
If the sensor cap is damaged or deteriorated, users need to purchase a new one. Every new cap
has a set of calibration codes which need to be input into the instrument. The specific input method will
be described in the instruction manual of sensor cap.
4.3.6
The probe that comes with the meter can be used directly. User should not take off the sensor
cap when it is not in use, nor should one swap the caps from different instruments. When being
installed, the sensor cap must be tightened, and the interior cannot be contaminated or wet.
5
Calibration and Measurement of Dissolved Oxygen
5.1
Connect the DO electrode
The meter uses 8-pin socket. When the electrode is connected to the meter, please rotate it slowly to
find the position of the bayonet and connect it, and then tighten the cap nut. Be careful not to pull the
cable forcefully to prevent poor contact and keep the plug clean and dry.
5.2
Preparation for calibration
5.2.1
DO units selection:
D
issolved oxygen units display in three forms: mg/L, ppm and %. Press to switch from mg/L→% or
ppm→%.
User can choose mg/L or ppm in Parameter Setting P4.4, but only a percentage (DO%) is
displayed in calibration.
5.2.2
Resolution selection
User can choose 0.01 or 0.1 mg/L (ppm) in parameter setting P4.1. After setting, the meter will display
resolution of 0.1 or 1 according to %.
5.2.3
Temperature unit selection
The temperature unit can be selected in parameter setting P6.1: °C or °F
5.2.4
Air pressure compensation
The instrument has automatic air pressure compensation function. The air pressure has been calibrated
before the product left the factory. So, in general users do not have to calibrate air pressure any more. If
