1、 Preparation before use

1. Calibration operation：
   • zero point calibrationPerform zero calibration in an anaerobic environment (such as by introducing high-purity nitrogen or using anaerobic water) to ensure that the instrument displays zero in the absence of dissolved oxygen.
   • Full calibrationPerform full-scale calibration in a saturated oxygen environment (such as air saturated water or standard solution) to make the instrument display consistent with the standard value.
   • periodic calibrationBased on the frequency of use, it is recommended to calibrate every 1-2 weeks or recalibrate after replacing the probe each time.
2. Probe inspection：
   • Check whether the membrane of the dissolved oxygen probe (such as polarographic or fluorescent) is intact, without damage or aging.
   • Confirm that the internal electrolyte of the probe is sufficient (the electrolyte of the polarographic probe needs to be replaced regularly).
   • Clean the surface of the probe to avoid dirt or biological attachment affecting the measurement.
3. Confirmation of environmental conditions：
   • Avoid using in strong electromagnetic interference environments (such as near high-voltage lines and large motors) to prevent signal interference.
   • Ensure that the measurement environment temperature is within the working range of the instrument (usually 0-50 ℃), and avoidharshTemperature affects the performance of the probe.

2、 Precautions for operation steps

1. Probe installation and immersion：
   • Slowly immerse the probe into the water body to be tested, avoiding rapid insertion that may cause bubbles to adhere to the surface of the probe and affect measurement accuracy.
   • Ensure that the probe is submerged and the immersion depth meets the requirements of the instrument (usually more than 2/3 of the probe length).
2. stable measurement：
   • Wait for the instrument reading to stabilize before recording the data (usually taking 3-5 minutes), to avoid reading fluctuations caused by water flow fluctuations or temperature changes.
   • Avoid touching the probe during the measurement process to prevent human interference.
3. temperature compensation：
   • The dissolved oxygen concentration is significantly affected by temperature, and it is necessary to activate the temperature compensation function (if supported by the instrument) or manually input the water temperature for correction.
   • If the instrument does not have temperature compensation function, it is necessary to measure the water temperature and refer to the dissolved oxygen saturation table for conversion.

3、 Environmental restrictions for use

1. Avoid pollution and corrosion：
   • Stay away from oil stains, chemical reagents, or highly corrosive substances to prevent contamination or damage to the probe membrane.
   • When used in harsh environments such as sewage treatment, it is necessary to install protective covers or regularly clean the probe.
2. Water flow and mixing：
   • Static water bodies (such as ponds and water tanks) need to be manually stirred or stirred to ensure uniformity and avoid local hypoxia.
   • Attention should be paid to fixing the probe in flowing water bodies (such as rivers and pipelines) to prevent it from being washed away or damaged by collisions.
3. Salinity effect：
   • In seawater or high salinity water bodies, it is necessary to choose a salt tolerant probe and calibrate the salinity parameters (if supported by the instrument).
   • Salinity changes can significantly affect the measurement results of dissolved oxygen, and measurements should be taken under stable salinity conditions.

4、 Maintenance and upkeep

1. Probe cleaning：
   • Rinse the surface of the probe with clean water after each use to avoid dirt or biological attachment.
   • Regularly clean the probe film with a soft cloth or cotton swab, and do not use hard objects to scrape it.
2. Probe storage：
   • Short term storage: Immerse the probe in distilled water or specialized storage solution to prevent membrane drying and aging.
   • Long term storage: Remove the probe, clean and seal it for storage, avoiding direct sunlight and high temperature environments.
3. Battery and power supply：
   • Regularly check the battery level and replace low battery cells in a timely manner to prevent data loss or instrument abnormalities.
   • When using AC power, ensure stable voltage and avoid damaging the instrument due to voltage fluctuations.

5、 Safety precautions

1. Electric shock prevention：
   • When used in humid environments or underwater, ensure that the instrument casing is well grounded to avoid the risk of electrical leakage.
   • It is prohibited to disassemble or repair the instrument while it is live.
2. Explosion proof environment：
   • Use explosion-proof dissolved oxygen meters in flammable and explosive environments such as gas stations and chemical plants, and comply with relevant safety regulations.
3. Operating Specifications：
   • Strictly follow the instrument manual for operation, and do not use beyond the range (such as measuring too high or too low dissolved oxygen concentration).
   • Avoid prolonged exposure of the probe to sunlight or high temperature environments to prevent accelerated membrane aging.

6、 Common fault handling

1. The reading is unstable：
   • Check if the probe is clean or replace it with a new one.
   • Confirm if the water flow is stable, or adjust the measurement position.
2. Low reading：
   • Check if the probe membrane is damaged or if the electrolyte leaks (polarographic probe).
   • Confirm whether to activate the temperature compensation function or manually adjust the water temperature.
3. The instrument cannot be turned on：
   • Check if the battery level or power connection is normal.
   • Restart the instrument or contact the manufacturer for repair.