How to Select a Portable Conductivity Meter? Detailed Comparison of Core Technical Parameters: CON300 vs CON340

Developed and mass-produced in-house by Shanghai Chunye Instrument Technology Co., Ltd., the CON300 and CON340 portable conductivity meter series adopt modular circuit design and multi-range electrode matching technology to deliver simultaneous four-parameter measurements of conductivity, TDS, salinity and temperature. Widely applied in environmental random water sampling, drinking water quality inspection, aquaculture monitoring and chemical intermediate solution testing, these meters rank among the mainstream portable TDS & salinity testers for domestic procurement. This paper analyzes the core technical advantages of CON300/CON340 portable conductivity meters from five aspects: measuring range structure, electrode compatibility, temperature compensation, hardware protection and intelligent operating system.

I. Wide-Range Adaptive Measurement Technology: Differentiated Range Design for Two Models

1. CON300: Measuring range: 0.000 µS/cm ~ 40.0 mS/cm, suitable for medium & low-conductivity water such as regular surface water, tap water and aquaculture water. Three optional electrode constants (k=0.01, 0.1, 1.0) are available. The k=0.01 electrode is specially configured for ultrapure water (<10 µS/cm) testing to eliminate measuring errors caused by trace ions in ultrapure water.

2. CON340: Measuring range: 0.000 µS/cm ~ 500.0 mS/cm. Its ultra-wide range covers concentrated brine, industrial wastewater and high-salinity chemical solutions. It additionally supports k=10.0 high-conductivity electrodes for detecting electrolytes above 40 mS/cm, satisfying test requirements for electroplating liquor, seawater and bittern.

Both instruments adopt high-precision voltage-dividing sampling circuits with graded optimized full-scale resolution, enabling seamless reading transition from trace 0.001 µS/cm to full-scale 0.1 mS/cm. The full-scale indication error is controlled within ±0.5% FS, meeting precision requirements for laboratory-grade portable analysis equipment.

II. Custom Calibration Technology for Multi-Specification Electrodes (Patent-Level Practical Core Technology)

2.1 P01 Menu Setting for Electrode K Factor

• CON300: k=0.01 (ultra-low range ultrapure water), k=0.1 (low-range soft water), k=1.0 (general water samples)

• CON340: k=0.1 / 1.0 / 10.0; extra k=10 option adapts to both low and high-concentration solutions

2.2 One-Touch CAL Single-Point Calibration Operation

Short press the 【CAL/INFO】 key under measurement mode to enter calibration mode. Submerge the electrode into standard calibration solution; once the stable "S" icon stops blinking on screen, adjust displayed value to match the nominal value of standard solution via up/down keys, then press 【ENT/HOLD】 to save slope parameters automatically. The whole calibration finishes within 30 seconds, ideal for on-site calibration without laboratory conditions and extensively used in industrial field inspections.

III. Multi-Dimensional Intelligent Temperature Compensation Technology to Eliminate Temperature-Caused Measurement Deviation

1. P03 Reference Temperature Setup: Customizable reference temperature ranging from 15.0℃ to 35.0℃, factory default set at national standard 25℃; users can reset per industrial norms (20℃ commonly used for aquaculture).

2. P04 Conductivity Temperature Coefficient: Linear coefficient adjustable between 0.00%~10.00%. Since pure water, tap water and seawater feature distinct ionic temperature coefficients, users can set corresponding values to activate accurate automatic temperature compensation (ATC).

3. P06 Temperature Offset Correction: Fine-tune temperature deviation within ±10℃ to offset inherent errors from built-in electrode temperature sensors. It guarantees ±0.2℃ temperature reading accuracy at 10℃~60℃, reliable for open-air field sampling and high-temperature workshop testing.

IV. IP67 Full-Body Protection & Ergonomic Hardware Design

1. Protection Performance: Tolerates short-term splashing and water spray; wipe dry to resume normal operation after accidental water contact. Prevents internal water ingress during humid or rainy field sampling, works stably under relative humidity ≤95% and adapts to most harsh environments except intensive corrosive gas and long-term strong sunlight exposure.

2. Power & Mechanical Structure: Powered by two AAA batteries; low-power chip extends service life with optional 10-minute auto power-off (configurable on P09 menu) to save power. Removable 90° electrode holder allows mounting multiple probes simultaneously, supporting handheld or bench-top placement. 120° wide-view backlit LCD clearly displays four sets of data (EC/TDS/Sal/Temp) under strong sunlight or dim surroundings.

3. Data Storage: Built-in memory chip stores up to 255 groups of measurement data. Call historical records quickly with up/down keys under measuring interface; "FULL" prompts when memory is full, and all logs can be cleared in one click via P10 menu to satisfy traceability filing for environmental spot inspection.

V. Full-Function Intelligent Menu System with Fine Control over 11 Customizable Parameters

• P05: TDS conversion factor adjustable 0.40~1.00 to fit regional water TDS conversion standards

• P07: HOLD reading lock function; auto-freezes stable readings to avoid constant screen monitoring during field tests

• P08: Key beep on/off switch for silent laboratory measurement

• P11: One-click factory reset restores original configuration when parameters get messed up, lowering instrument setup difficulty

VI. Selection Guide for CON300 & CON340

1. Choose CON300: Cost-effective option for routine surface water, drinking water and aquaculture testing where sample conductivity ≤40 mS/cm.

2. Choose CON340: Preferred for high-salinity wastewater, seawater, bittern and concentrated electrolyte requiring ultra-wide measuring range up to 500 mS/cm.