How to use the dissolved oxygen meter
Preparation before use of the dissolved oxygen meter
1. Initial Probe Inspection
① Remove the red and black plastic covers, as it is designed for shipping purposes and can be thrown away.
② Soak the bottom 2.5cm of the probe in the electrolyte to wet the sensor.
③ Gently swirl the electrolyte to rinse the film, then refill with clean electrolyte; tap the edge of the film with your fingertips to ensure no air bubbles and separate from the water.
④ Avoid damaging the film, do not directly tap the bottom of the film.
⑤ Make sure the rubber O-ring is correctly seated in the diaphragm cover.
⑥ With the sensor facing down, turn the membrane cover clockwise, and some electrolyte will overflow.
2. Dissolved Oxygen Meter Calibration
For maximum accuracy, it is recommended that the instrument be calibrated frequently. Calibration procedures for instrument standards are usually two values: 0.0% (zero point), 100% (slope). The calibration of the instrument is simple. Before the calibration, make sure that the probe is installed correctly and fully melted, and the probe is in a measurable state. Preliminary preparation: Pour a small amount of HI7040 zero-oxygen liquid into a beaker. If possible, use a plastic beaker to reduce EMC interference. Make sure electricity is measurable. Press the ON/OFF key to turn on the instrument. For calibration, it is recommended to wait 15 minutes and adjust the electricity. Set an appropriate altitude factor and set the salinity factor to zero.
⑴ Zero point calibration
① Insert the battery into the HI7040 zero oxygen solution, and stir gently for 2-3 minutes
② Press the CAL key, the "~" symbol and the word "NOT READY" will flash until the reading is stable
③ Once the reading is stable and the deviation is within the range, "CFM" starts to flash, press the CFM key to confirm the "0.0%" reading
④ Press the CAL key, the instrument will return to the measurement mode and record the zero point calibration data.
⑵ Slope calibration It is recommended to perform slope calibration in air. Clean the battery with plenty of clean water to remove the residual zero oxygen liquid on the battery.
① Dry the electric head and wait for a few minutes for the reading to stabilize. The "~" symbol and the word "NOT READY" will flash until the reading is stable.
② Once the reading is stable, "CFM" starts flashing, press the "CFM" key to confirm the "100.0%" D.O. value.
③ Once the reading is stable and within the tolerance range. The instrument will save the data (while adjusting the slope point), the instrument will record the zero calibration data, and return to the measurement mode.
④ If the reading is not close to the selected value, the word "WRONG" will flash, and if the reading is out of range, the word "WRONG" will flash at the same time.
3. Dissolved Oxygen Meter Operation Guide
1. DO measurement Make sure the instrument is calibrated, remove the protective cover, and then immerse the probe in the sample solution to be measured. Also make sure that the temperature sensor is also immersed in the sample and wait for the reading to stabilize (approximately 1 minute or so). The dissolved oxygen value is displayed on the main screen and the lower screen shows the temperature. Press the RANGE key, the value is converted between ppm and saturation percentage.
2. Temperature measurement The instrument has a built-in temperature probe, and the probe should reach thermal equilibrium with the outside world before measurement, which may take several minutes. The larger the temperature difference, the longer it will take.
① If "---" appears on the screen and the word "NO Probe" flashes, it indicates that the dissolved oxygen probe is connected incorrectly or the measured temperature is out of range, or the probe may be damaged.
② If the measured temperature exceeds the range, the word "℃" will flash.
③ If the reading exceeds the range, all range values or flashing
④ Make sure the instrument has been calibrated before measuring the sample
⑤ If it is necessary to successfully measure multiple samples and obtain readings, the probe must be thoroughly cleaned with deionized water before the probe is immersed in the sample.
