Hach LDO User Manual

Also see for LDO: Addendum-Operation User manual

Hach LDO User Manual Manual pdf 25 page image

25Operationthree minutes for the reading to stabilize is typical, however, if it has not stabilized after45 minutes, the display will ready “Unable to Calibrate”. After calibration, one of theresponses in Table 5 on page 26 will be displayed.11. Follow the prompts to return the sensor to the process.5.6.2 Sample Cal—Calibration by Comparison to a Winkler Titration1. From the Main Menu, select SENSOR SETUP and confirm.2. Select the appropriate sensor if more than one is attached and confirm.3. Select CALIBRATE and confirm.4. Select SAMPLE CAL. Select the available Output Mode (Active, Hold, or Transfer)from the list box and confirm.Note: An output that has been placed in Hold or Transfer status will be automatically released whenthe calibration is complete.5. Remove the sensor from the process stream and gently wipe with a wet cloth toremove all debris and biological growth. Remaining debris will affect the WinklerMethod of analysis.6. Measure 1000 mL of deionized water. Allow the water to come to the thermal anddissolved oxygen equilibrium (approximately 20 minutes).7. Fill a standard BOD bottle and then place the sensor in a beaker containing theremainder of the deionized water.8. Perform the Winkler Tritration using Cat. No. 146900 Winkler Test Kit on the deionizedwater in the BOD bottle while waiting for the process sensor to stabilize.9. Move the sensor to the sample.10. The display will show “Press ENTER when Stabilized” and the current DO andtemperature readings. When the reading is confirmed or when the reading has beenaccepted as stable, the display will change to an entry screen. If ENTER is notpressed, the sensor will determine when the reading is stable. Two to three minutesfor the reading to stabilize is typical, however, if it has not stabilized after 45 minutes,the display will show “Unable to Calibrate”.11. When a stable reading has been accepted, the display will show “Sample Cal” and anarea for entry of the value obtained from the comparison method. When the entryscreen is displayed, enter the value from the hand-held or winkler titration and confirm.12. After calibration, one of the responses in Table 5 on page 26 will be displayed.5.6.3 Sample Cal—Calibration by Comparison to a Hand-held DO Analyzer1. Place the dissolved oxygen sensor as close to the LDO sensor as possible.2. Wait for the hand-held DO analyzer to stabilize.3. From the Main Menu, select SENSOR SETUP and confirm.4. Select the appropriate sensor if more than one is attached and confirm.