FangZhou DDS-200 Portable Conductivity Meter

Overview

The FangZhou DDS-200 Portable Conductivity Meter is a microprocessor-controlled, single-parameter electrochemical analyzer engineered for precision and operational robustness in both laboratory and field-deployed environments. It operates on the principle of two-electrode AC conductivity measurement—applying a low-frequency alternating current to minimize polarization effects and electrode fouling—enabling stable, reproducible readings across aqueous solutions with wide dynamic range. The instrument simultaneously calculates and displays conductivity, temperature-compensated resistivity, TDS (based on user-defined conversion factor), and practical salinity (in ppt), all traceable to SI-derived units. Its design adheres to fundamental metrological requirements for Class 1.0 instruments per GB/T 11018–2021 (equivalent to IEC 60746-3:2020 for conductivity meters), ensuring compliance with routine quality control protocols in regulated laboratories.

Key Features

• Seven-range automatic scaling (0.000–0.200 µS/cm to 20.0–200.0 mS/cm), optimized for DJS cell constants of 0.01, 0.1, 1.0, and 10.0 cm⁻¹
• High-resolution LCD with touch-sensitive keypad—designed for gloved operation and reduced mechanical wear
• Integrated ATC (Automatic Temperature Compensation) with selectable β coefficient (default 2.0%/°C), supporting both automatic and manual temperature input
• IP65-rated enclosure—dust-tight and protected against water jets from any direction—validated for use in humid labs, wastewater treatment sites, and outdoor sampling campaigns
• Dual-power architecture: internal rechargeable lithium-ion battery (≥12 h continuous operation) + universal AC/DC adapter (100–240 V, 50/60 Hz)
• Non-volatile memory preserving calibration coefficients and 200 timestamped measurement records—even after power loss
• Low-voltage, high-stability analog front-end with 24-bit A/D conversion and digital filtering for enhanced signal-to-noise ratio

Sample Compatibility & Compliance

The DDS-200 is validated for use with deionized water, tap water, seawater dilutions, industrial process streams, biological buffers, and food-grade extracts. Its electrode interface supports standard BNC and mini-DIN connectors compatible with common DIN/ISO-compliant conductivity cells. The instrument meets ISO 9001:2015 quality management system requirements and is routinely deployed in laboratories operating under GLP (Good Laboratory Practice) frameworks. While not FDA 21 CFR Part 11–compliant out-of-the-box (lacking electronic signature and audit trail functionality), its data export capability via USB interface enables integration into validated LIMS environments where raw measurements are archived with metadata (date/time, operator ID, electrode ID, calibration status).

Software & Data Management

Data retrieval is performed via USB port using FangZhou’s proprietary PC software (Windows 10/11 compatible), which imports CSV-formatted logs containing conductivity (µS/cm), TDS (g/L), resistivity (Ω·cm), salinity (ppt), temperature (°C), and measurement timestamp. The software supports batch export, trend plotting, and comparative analysis across multiple samples. All stored values retain their original resolution and unit context; no interpolation or rounding is applied during transfer. Calibration history—including date, standard used (e.g., KCl 1413 µS/cm), slope, and offset—is embedded in each record. For regulatory workflows, users may manually annotate entries with sample IDs and location tags prior to archiving.

Applications

• Environmental monitoring: Surface water, groundwater, and effluent conductivity profiling per ASTM D1125 and ISO 7888
• Pharmaceutical QC: USP compliant purified water and water-for-injection (WFI) conductivity verification at 25 °C
• Food & beverage: Monitoring brine concentration, syrup solids, and cleaning-in-place (CIP) rinse efficacy
• Academic teaching labs: Demonstrating electrolyte behavior, ion mobility, and temperature dependence of conductivity
• Biochemistry: Buffer preparation validation and cell culture media conductivity checks
• Education & vocational training: Hands-on electrochemical fundamentals with real-world calibration and troubleshooting exercises

FAQ

What cell constant options are supported?
Four standardized cell constants: 0.01 cm⁻¹ (ultra-low conductivity), 0.1 cm⁻¹ (pure water), 1.0 cm⁻¹ (standard lab use), and 10.0 cm⁻¹ (high-salinity or concentrated solutions).

Does the DDS-200 support multi-point calibration?
No—it performs single-point calibration using one certified standard (e.g., 1413 µS/cm KCl). Multi-point calibration is not required for Class 1.0 accuracy within its specified ranges.

Is temperature compensation mandatory?
No—both automatic (ATC) and manual temperature entry modes are available. Users may disable compensation for research applications requiring raw uncorrected values.

How is calibration data retained during battery replacement?
All calibration parameters and 200 measurement records are stored in non-volatile flash memory; no data loss occurs during power interruption or battery swap.

Can the instrument be used for seawater analysis?
Yes—within the 0.00–80.00 ppt salinity range and up to 200 mS/cm conductivity. For full oceanic salinity (≈35 ppt), ensure proper electrode cleaning post-measurement to prevent chloride deposition.