1、 Hardware troubleshooting
1. Optical system abnormality
Phenomenon: Large data fluctuations, no readings or display of "optical path failure".
Possible reasons:
Optical window contamination (dust, oil stains, reagent crystallization).
The light source (LED/xenon lamp) is aging or damaged.
The sensitivity of photovoltaic cells (photodetectors) decreases.
Troubleshooting steps:
Clean optical window: Dip a dust-free cloth in ethanol and gently wipe to avoid scratching the surface.
Check the intensity of the light source: Confirm the stability of the light source output through the device self-test function or an external optical power meter.
Test the photovoltaic cell: block the light path and observe whether the signal changes as expected (if there is no change, it needs to be replaced).
Case: A sewage treatment plant equipment had its optical window covered by algae, resulting in a COD reading that was 50% lower. After cleaning, it returned to normal.
2. Blockage in the flow system
Phenomenon: Injection failure, unstable flow rate, or alarm of "flow path blockage".
Possible reasons:
Reagent crystallization (such as silver sulfate precipitation at low temperatures).
Sedimentation of particulate matter (such as sediment and fibers) in water samples.
Aging or improper installation of peristaltic pump tubing.
Troubleshooting steps:
Rinse flow path: Reverse rinse the injection tube, reaction tank, and drain tube with deionized water.
Check the pump tube: Confirm that the pump tube is not damaged, loose, or tangled, and replace it if necessary (usually every 3-6 months).
Filter water sample: Install a pre filtration device (such as a 50 μ m filter) at the injection port to reduce the entry of particulate matter.
Case: The equipment of a printing and dyeing factory was blocked by dye particles due to the lack of filters installed, and the reaction tank resumed operation after cleaning.
3. Reagent system malfunction
Phenomenon: Insufficient reagent alarm, incomplete digestion, or abnormal color.
Possible reasons:
The liquid level of the reagent bottle is too low or leaking.
Reagent deterioration (such as potassium dichromate getting wet and clumping).
Leakage or blockage of reagent pipeline.
Troubleshooting steps:
Check the remaining amount of reagents: Confirm the adequacy of reagents through equipment level sensors or visual inspection.
Replace reagent: If the color of the reagent darkens (such as potassium dichromate oxidation) or precipitation occurs, it should be replaced immediately.
Test tubing: Inject air into the tubing with a syringe and check for air bubbles (if there are no bubbles, it will be blocked).
Case: Equipment in a petrochemical enterprise leaked reagents due to aging and cracking of reagent pipelines. The problem was solved after replacing the pipelines.
2、 Troubleshooting of Software and Communication Malfunctions
1. Data anomalies (fluctuations, drift, fixed values)
Phenomenon: Data suddenly jumps, slowly rises/falls, or remains constant.
Possible reasons:
Software algorithm error (such as baseline drift compensation failure).
Communication interruption leads to data loss or duplication.
Sensor signal interference (such as electromagnetic fields, power fluctuations).
Troubleshooting steps:
Restart the device: Use the software or hardware reset button to restart and clear temporary faults.
Check communication: Confirm that the communication protocol (such as Modbus RTU/TCP), baud rate, and address settings between the device and the upper computer (PLC, SCADA) are consistent.
Shielding interference: Keep the equipment away from strong electromagnetic sources such as frequency converters and high-voltage lines, or install signal isolators.
Case: A power plant equipment suffered a data loss rate of 30% due to damaged communication cables. After replacing the cables, it was restored to normal.
2. Firmware/software crashes
Phenomenon: Device crashes, unresponsive touch screen, or frequent restarts.
Possible reasons:
The firmware version is outdated or has bugs.
Memory (SD card/Flash) is damaged.
Unstable power supply leads to data writing errors.
Troubleshooting steps:
Update firmware: Download the latest version from the manufacturer's official website and upgrade via USB flash drive or network.
Format storage: After backing up data, perform low-level formatting on the storage to eliminate the influence of bad blocks.
Check the power supply: Use a multimeter to measure the input voltage (such as 24V DC), ensuring that the fluctuation range is less than ± 5%.
Case: The data recording of a sewage treatment plant equipment was interrupted due to a firmware bug, and the problem was resolved after upgrading.
3、 Environmental and operational troubleshooting
1. Environmental interference
Phenomenon: The data is abnormal during a specific time period (such as being higher in the afternoon and lower at night).
Possible reasons:
Excessive temperature (>40 ℃) can cause reagent evaporation or sensor performance degradation.
Excessive humidity (>85%) can cause circuit board short circuits or optical window condensation.
Direct sunlight causes an increase in internal temperature of the equipment.
Troubleshooting steps:
Improving the environment: Move the equipment to a well ventilated, cool, and dry place, or install air conditioning/dehumidifiers.
Install protective cover: Use a sunshade or dust box to reduce the impact of environmental factors.
Temperature compensation: If the device supports it, enable the temperature compensation function to correct the impact of ambient temperature on the measurement.
Case: A certain agricultural drainage monitoring station equipment experienced reagent volatilization due to high temperatures in summer, and the data became stable after installing a sunshade.
2. Improper operation causing malfunction
Phenomenon: Frequent alarms, calibration failures, or shortened lifespan of the equipment.
Possible reasons:
Not following the prescribed procedures (such as calibration without cleaning).
Calibration solution expired or contaminated.
The maintenance cycle is too long (such as not replacing the pump tube for more than 1 year).
Troubleshooting steps:
Standardized operation: Strictly follow the instructions for calibration, cleaning, and maintenance.
Check the calibration solution: Confirm that the calibration solution is within its validity period and has not been contaminated (such as turbidity or discoloration).
Develop maintenance plan: Establish equipment files to record each maintenance time, content, and replacement parts.
Case: A food factory equipment had a data deviation of 20% due to the operator's failure to clean the reaction tank and directly calibrate it. After re cleaning, it returned to normal.
4、 Systematic troubleshooting process
Observation phenomenon: Record the time, frequency, and specific manifestations of the fault (such as abnormal data values and alarm codes).
Isolation issue: locate the faulty module through replacement methods (such as replacing reagents, pump tubes, sensors).
Analyze the root cause by combining device logs, historical data, and environmental conditions.
Implement repair: Take measures such as cleaning, replacement, adjustment, or upgrading based on the investigation results.
Verification effect: After repair, run the device for at least 24 hours to confirm that the fault has not recurred and the data is stable.
Preventive measures: Optimize operational processes, strengthen environmental control, or shorten maintenance cycles to avoid similar failures from happening again.