Hach 900 MAX 5.4.4Dissolved Oxygen Probe Calibration, Section, Calibrating the D.O. Temperature

Section 5

5.4.3Dissolved Oxygen Probe Temperature Programming

1.From the Main Menu, select OPTIONS>ADVANCED OPTIONS>DATALOG

2.Highlight Select Inputs using the UP and DOWN keys and press SELECT.

3.Highlight D.O. Temp. using the UP and DOWN keys, then press SELECT.

4.Cycle between Logged and Not Logged, then press ACCEPT.

5.Enter a logging interval using the numeric keypad, then press ACCEPT. Valid logging intervals are shown on the status bar.

6.Select temperature units (°C, °F) using CHANGE CHOICE. Press ACCEPT.

5.4.4Dissolved Oxygen Probe Calibration

The Dissolved Oxygen Probe is shipped without an electrolyte or membrane installed. Install these items before initial use.

1.Connect a suitable power supply to the sampler, and power up the unit by pressing the ON button.

Note: The membrane of a charged sensor must be kept moist. If the membrane is allowed to dry completely, the electrolyte film between the membrane and the platinum will evaporate, destabilizing the sensor. If the sensor will be out of water for more than 30 minutes, put a small amount of water in the silicon soaking cap, and install it over the protective guard. Lift the edge of the cap to break the seal as it is being removed. This will prevent a vacuum from forming inside the soaking cap while it is being removed which can result in the membrane becoming stretched.

2.From the Main Menu, select OPTIONS > ADVANCED OPTIONS >

CALIBRATION > DO.

3.Enter the ambient air temperature (the current reading is displayed for reference) using the numeric keypad.

4.Enter the elevation above sea level for the specific location.

5.Enter the membrane thickness. The operation of the sampler will be affected by membrane thickness for the oxygen sensor.

For general purpose applications, the 1-Mil membrane is standard. This membrane allows measurements in the 0 to 20 ppm range of dissolved oxygen and provides the best response time and durability.

The 2-Mil membrane can be used to measure up to 40 ppm dissolved oxygen. Its increased thickness slows the response time of the sensor, but this membrane has increased resistance to cuts and tears. For this reason, it is recommended for use in wastewater aeration basins where solids in the water are in rapid motion.

6.Enter the chlorinity (salinity) of the flow stream (typical wastewater is zero, sea water is higher).

7.Place the D.O. probe in open air and press any key. The sampler will wait for the reading to stabilize before storing the calibration value. The screen will automatically return to the calibration menu.

Calibrating the D.O. Temperature

1.Place the probe and the thermometer in a liquid.

2.Wait for the temperature reading to stabilize.

3.Enter the actual temperature of the liquid.

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