METER ES-2 Conductivity Sensor
| Brand | METER |
|---|---|
| Origin | USA |
| Manufacturer Type | Authorized Distributor |
| Import Status | Imported |
| Model | ES-2 |
| Measurement Parameter | Single (Electrical Conductivity) |
| Form Factor | Pen-style |
| Deployment Environment | In-pipe, in-tank, and pore-water applications |
| EC Range | 0–120 dS/m |
| TDS Range | Derived from EC (default 0.5–0.7 conversion factor) |
| Resistivity Range | 0.0083–1000 kΩ·cm (calculated inverse) |
| Salinity Range | 0–60 ppt (based on PSS-78 standard) |
| Temperature Range | –40 to +60 °C |
| Accuracy | EC: ±0.01 dS/m or ±10% (whichever is greater) |
| Temp | ±1 °C |
| Resolution | EC: 0.001 dS/m |
| Temp | 0.1 °C |
| Output Protocol | SDI-12 or DDI serial |
| Compatible Data Loggers | METER ZL6 series or any SDI-12–compliant logger with 3.6–15 VDC excitation |
| Dimensions | 10.9 cm (L) × 2.4 cm (W) |
| Cable | 5 m standard (custom up to 75 m) |
| Connector | 3.5 mm stereo jack or tinned leads |
| Power Supply | 3.6–15 VDC |
| Current Draw | 20–28 mA (active), 0.03 mA (standby) |
| Startup Time | 100–250 ms (SDI-12 dependent) |
| Measurement Duration | 25–50 ms |
| Compliance | ISO 9001:2015 certified manufacturing |
| CE marked per EM directive EN ISO/IEC 17050 | 2010 |
| Mechanical Interface | 1-inch NPT threaded body with optional T-fitting for pipe mounting |
Overview
The METER ES-2 Conductivity Sensor is an industrial-grade, pen-style electrochemical probe engineered for continuous, in-situ measurement of electrical conductivity (EC) in aqueous environments—including pressurized pipelines, storage tanks, leachate collection systems, and narrow soil pore spaces. Based on two-electrode AC conductometric principles, the ES-2 applies a low-frequency alternating current across its stainless-steel sensing electrodes to minimize polarization effects and electrode fouling—ensuring stable performance in high-ionic-strength or particulate-laden waters. Its compact, NPT-threaded housing enables direct integration into process lines without flow cell requirements, while its wide operating temperature range (–40 to +60 °C) supports deployment in freeze-prone infrastructure and high-temperature industrial effluents. Designed as a field-deployable component within METER’s environmental monitoring ecosystem, the ES-2 delivers traceable, high-resolution EC data compatible with long-term trend analysis, regulatory reporting, and real-time process control.
Key Features
- Two-electrode AC conductometric design optimized for robustness in variable water chemistry and moderate fouling conditions
- High-resolution measurement capability: 0.001 dS/m resolution across full 0–120 dS/m range, supporting both freshwater and hypersaline applications
- Integrated Pt1000 temperature sensor with ±1 °C accuracy and 0.1 °C resolution for automatic temperature compensation (ATC) per ASTM D1125 and ISO 7888
- SDI-12 and DDI dual-protocol support ensures interoperability with industry-standard environmental data loggers—including METER ZL6, Campbell Scientific CR-series, and Onset HOBO UX120 platforms
- IP68-rated housing with 316 stainless steel electrodes and chemically resistant epoxy encapsulation for extended service life in aggressive media
- Low-power operation (20 mA active, 30 µA standby) enabling solar-powered remote deployments with multi-year battery life
- NPT 1-inch threaded body with optional T-fitting kit for secure, leak-tight installation in ½–2 inch piping systems
Sample Compatibility & Compliance
The ES-2 is validated for use in potable water, wastewater, irrigation return flows, brine solutions, and saturated soil pore water. It meets material compatibility requirements for Class I, Division 2 hazardous locations (per UL 1203) when installed with appropriate conduit seals. All calibration and verification procedures align with EPA Method 120.1 and ASTM D5391 for conductivity measurement. Manufacturing adheres to ISO 9001:2015 quality management standards, and CE marking confirms conformity with EU Electromagnetic Compatibility Directive 2014/30/EU and Low Voltage Directive 2014/35/EU. While not intrinsically safe for Zone 0/1 environments, it is routinely deployed in GLP-compliant groundwater monitoring networks and FDA-regulated pharmaceutical water system validation protocols where SDI-12 data integrity and audit-ready timestamping are required.
Software & Data Management
Raw EC and temperature values are transmitted digitally via SDI-12 or DDI protocol—eliminating analog signal degradation and enabling bit-for-bit reproducibility. When paired with METER’s ZL6 data logger, measurements are automatically time-stamped, stored with metadata (battery voltage, excitation status, CRC checksum), and accessible remotely via cellular or LoRaWAN uplink. Exported CSV files include ISO 8601 timestamps and support direct ingestion into LIMS platforms compliant with 21 CFR Part 11 (with optional electronic signature modules). The sensor’s firmware supports configurable measurement intervals (1 min to 24 h), burst-mode sampling, and programmable alarm thresholds—facilitating automated anomaly detection in critical water quality applications.
Applications
- Real-time salinity monitoring in desalination plant intake and brine discharge streams
- Leachate conductivity tracking in landfill liner integrity assessments (EPA SW-846 Method 9012B)
- Soil solution EC profiling when co-deployed with TEROS 12 soil moisture and temperature sensors for integrated solute transport modeling
- Process water quality assurance in food & beverage, semiconductor, and pharmaceutical manufacturing (USP , EP 2.2.38)
- Corrosion potential estimation in cooling tower circuits via conductivity-driven scaling index calculations
- Regulatory compliance reporting for NPDES permits requiring continuous EC monitoring at outfall points
FAQ
What calibration standards are recommended for the ES-2?
Standard KCl solutions traceable to NIST SRM 3520a (e.g., 1.413 mS/cm at 25 °C) are advised for two-point calibration. Field verification using a second standard (e.g., 12.88 mS/cm) is recommended for high-range applications.
Can the ES-2 be used in seawater or saturated brine?
Yes—the 0–120 dS/m range covers natural seawater (~50 dS/m) and saturated NaCl solutions (~110 dS/m). For extended exposure, periodic cleaning with dilute HCl is advised to remove carbonate deposits.
Is temperature compensation automatic and configurable?
Yes—linear ATC per ASTM D1125 is applied onboard using the integrated Pt1000 sensor; the temperature coefficient (β) is fixed at 2.14%/°C but can be overridden via logger command if site-specific compensation is required.
Does the ES-2 support MODBUS or analog output?
No—it outputs only digital SDI-12 or DDI signals. Analog conversion requires an external signal conditioner or a data logger with analog input capability and built-in EC calculation firmware.
What is the maximum cable length for reliable SDI-12 communication?
Up to 75 meters is supported with shielded, twisted-pair cable and proper grounding. Beyond 30 meters, use of a line driver or repeater is recommended to maintain signal integrity in electrically noisy environments.
