1、 Installation and usage environment

1. Installation location selection
   • Avoid sources of interferenceStay away from strong electromagnetic fields (such as motors, frequency converters), vibration sources, or high-temperature areas to prevent signal interference or sensor damage.
   • Flow rate controlDuring pipeline installation, ensure stable fluid flow velocity (usually recommended at 0.3~3 m/s) to avoid sedimentation caused by low flow velocity or cavitation caused by high flow velocity.
   • vertical installationPriority should be given to installing sensors vertically (with electrodes perpendicular to the ground) to reduce bubble adhesion or sediment accumulation (flow rate adjustment devices should be installed for horizontal installation).
2. Environmental conditions limitations
   • temperature rangeConfirm the working temperature range of the sensor (such as -10 ℃~+80 ℃) to avoid electrode aging or seal failure caused by exceeding the range.
   • humidity controlIn humid environments such as outdoors and basements, sensors with a protection level of IP65 or higher should be selected to prevent internal circuit short circuits.
   • Explosion-proof requirementsIn flammable and explosive places such as chemical plants and gas stations, explosion-proof sensors (such as ATEX/IECEx certified models) should be selected.

2、 Media compatibility

1. chemical compatibility
   • Electrode material matchingSelect electrode material based on solution composition:
     • Stainless steel electrodeSuitable for general aqueous solutions such as tap water and cooling water, but with limited corrosion resistance.
     • Titanium electrodeResistant to corrosion from seawater and chloride solutions, suitable for marine monitoring or chemical processes.
     • Platinum electrodeResistant to strong acids and alkalis (such as sulfuric acid and sodium hydroxide), but at a higher cost.
     • graphite electrodeSuitable for high temperature or highly corrosive media (such as molten salt), but with lower accuracy.
   • Selection of sealing materialsConfirm whether the O-ring or gasket material (such as NBR, EPDM, PTFE) is resistant to medium corrosion (PTFE sealing is required for strong acids).
2. Physical state adaptation
   • Suspended solids controlIf the solution contains particulate impurities (such as sewage or slurry), a filter (with a filtration accuracy of ≥ 50 μ m) should be installed upstream of the sensor to prevent electrode contamination or wear.
   • Bubble exclusionIn media with high gas solubility, such as beer and carbonated beverages, it is necessary to install an air purifier or adopt a vertical installation method to avoid measurement errors caused by bubbles adhering to the electrode.

3、 Calibration and maintenance

1. periodic calibration
   • Calibration frequencyDetermine the calibration cycle based on the usage scenario (such as daily calibration in the laboratory and weekly calibration in the industrial field).
   • Standard solution selectionUse standard solutions that match the conductivity range of the tested solution (such as 147 μ S/cm, 1413 μ S/cm, 12.88 mS/cm).
   • calibration method：
     • Two-point calibrationCalibrate separately with low and high concentration standard solutions to improve linearity (suitable for high-precision requirements).
     • Single point calibrationCalibrate zero or range with a single standard solution (suitable for rapid detection scenarios).
   • temperature compensationIf the sensor supports temperature compensation, it is necessary to ensure that the temperature probe is working properly (temperature error ≤± 0.5 ℃), otherwise the temperature value needs to be manually entered.
2. routine maintenance
   • Clean electrode：
     • Wipe with a soft clothGently wipe the surface of the electrode with a dust-free cloth or cotton swab dipped in deionized water to avoid scratches.
     • chemical cleaningIf the electrode scales (such as calcium and magnesium deposition), it can be soaked in dilute hydrochloric acid (1%~5%) for 5-10 minutes, and then rinsed clean with deionized water.
   • Check the sealing performanceRegularly check whether the sensor interface and cable joints are leaking (you can apply soapy water to the interface and observe if there is any bubbling).
   • Replace consumablesReplace vulnerable parts such as sealing rings and electrodes according to the instructions (such as EPDM sealing rings, it is recommended to replace them every 1-2 years).

4、 Electrical connections and signal processing

1. Electrical Connection Specification
   • Power requirementsConfirm that the sensor power supply voltage (such as 24 V DC, 220 V AC) matches the control system to avoid reverse connection or overvoltage damage.
   • grounding protectionThe sensor housing needs to be reliably grounded (grounding resistance<10 Ω) to prevent static electricity or lightning interference.
   • shielded cableWhen transmitting over long distances (>10 m), use shielded cables (such as RVVP type) and single ended grounding to reduce electromagnetic interference.
2. Key points of signal processing
   • Output signal typeSelect the signal type (such as 4-20 mA, RS485, 0-5 V) according to the control system requirements to avoid signal attenuation or distortion.
   • Anti interference measures：
     • isolatorIn strong interference environments, install signal isolators (such as 4-20 mA isolation modules) to cut off the ground loop.
     • filtering algorithmSet up digital filtering (such as moving average filtering) in PLC or DCS to eliminate instantaneous interference.
   • Range matchingEnsure that the sensor range covers the actual measurement range (such as a measurement range of 0-200 mS/cm, sensors with a range ≥ 200 mS/cm should be selected) to avoid signal saturation.

5、 Safety and operational standards

1. Operational Security
   • Power-off operationBefore disassembling or cleaning the sensor, the power must be cut off (such as turning off the 24 V DC power switch) to prevent electric shock.
   • Anti scalding measuresWhen operating in high-temperature media (such as steam condensate), it is necessary to wear insulated gloves to avoid burns.
   • Corrosion protectionWhen in contact with highly corrosive media (such as concentrated sulfuric acid), it is necessary to wear protective clothing, goggles, and acid resistant gloves.
2. Storage and transportation
   • Short term storageWhen the sensor is not in use, it is necessary to keep the electrode moist (such as soaking in deionized water) to prevent drying and performance degradation.
   • Long-term storageIf long-term storage is required (>3 months), the sensor should be cleaned, the electrode should be wrapped in a protective cover, and stored in a dry, cool place (temperature 5 ℃~25 ℃, humidity<60%).
   • Transportation requirementsAvoid severe vibration or collision during transportation to prevent electrode deformation or internal component damage.

6、 Typical faults and troubleshooting

7、 Additional selection suggestions

1. Select based on application scenarios
   • Laboratory high-precision measurementSelect platinum electrodes, temperature compensation function, and sensors that support multi-point calibration (such as Mettler Toledo InLab 710).
   • Industrial online monitoringSelect sensors with titanium electrodes, IP68 protection level, and 4-20 mA output (such as Endress+Hauser CLS15).
   • Portable detectionChoose lightweight design, built-in battery, and sensors that support data storage (such as Hanna Instruments HI98303).
2. Balancing Cost and Performance
   • limited budgetChoose sensors with stainless steel electrodes, single point calibration, and basic protection level (such as Omega CDH-500).
   • long-runningInvest in platinum electrodes, explosion-proof design, and sensors with automatic cleaning function (such as Siemens SITRANS LC300) to reduce maintenance costs.