JENCO 3675 Industrial Online pH/ORP Controller

Overview

The JENCO 3675 Industrial Online pH/ORP Controller is a compact, DIN-rail mountable process analyzer engineered for continuous, real-time monitoring and control of acidity (pH) and redox potential (ORP) in industrial water treatment, chemical processing, food & beverage production, and wastewater management systems. Based on potentiometric measurement principles, the controller interfaces with standard glass pH electrodes and noble-metal ORP sensors to convert electrochemical potential differences into calibrated digital readings. Its dual-parameter capability eliminates the need for separate instruments when both acid-base equilibrium and oxidation-reduction status must be tracked simultaneously—such as in chlorine dosing control, electroplating bath monitoring, or bioreactor pH/sterility assurance. The device operates within a robust 24 VDC power architecture and complies with IEC 61000-6-2 (EMC immunity) and IEC 61000-6-4 (EMC emission) standards for industrial environments.

Key Features

• Dual-function measurement: Simultaneous pH and ORP quantification using a single instrument platform, reducing system footprint and integration complexity.
• High-resolution LCD display with backlight: Presents real-time pH (–2.00 to 14.00), ORP (–1999 to +1999 mV), temperature (0–100 °C), and status indicators including electrode slope and offset diagnostics.
• Automatic temperature compensation (ATC): Uses integrated Pt1000 or external RTD input to correct pH readings per Nernst equation, ensuring accuracy across dynamic thermal conditions.
• Two fully configurable relay outputs: Support SPDT switching with adjustable hysteresis; suitable for pump activation, alarm signaling, or solenoid valve control in closed-loop dosing applications.
• Isolated 4–20 mA analog output: Provides galvanically isolated current transmission compatible with PLCs, DCS systems, and SCADA networks—fully scalable and linear across user-defined measurement spans.
• Standard 1/4 DIN plastic enclosure (96 × 48 × 172 mm): IP65 front panel rating ensures resistance to dust and low-pressure water jets; designed for panel mounting in control cabinets or field enclosures.

Sample Compatibility & Compliance

The JENCO 3675 is compatible with industry-standard combination pH/ORP electrodes—including double-junction, gel-filled, and refillable liquid-junction types—as well as dedicated ORP sensors with platinum or gold sensing elements. It supports calibration protocols aligned with ASTM D1293 (standard test method for pH of water) and ISO 10523 (water quality — determination of pH). While not certified for SIL-rated safety loops, its relay logic conforms to IEC 61508 functional safety guidelines for basic process control tasks. The unit meets CE marking requirements for electromagnetic compatibility and low-voltage directive compliance. For regulated environments, it supports manual audit trails via local event logging (power-on, calibration, relay activation), though full 21 CFR Part 11 compliance requires integration with validated third-party data acquisition software.

Software & Data Management

The 3675 operates as a standalone controller without embedded firmware-based data logging or cloud connectivity. All configuration—including calibration constants (one-point or two-point pH, mV offset for ORP), relay setpoints, hysteresis values, and output scaling—is performed via intuitive front-panel navigation using membrane keys. Calibration history and sensor diagnostic metrics (e.g., asymmetry potential, slope %) are viewable in real time but not exportable. For centralized supervision, the isolated 4–20 mA output enables seamless integration into existing plant historian systems (e.g., OSIsoft PI, Emerson DeltaV, Siemens Desigo CC). Optional analog-to-digital gateways may be deployed to enable Modbus RTU communication where protocol-level interoperability is required.

Applications

• Chemical dosing control in cooling towers and boiler feedwater systems, where precise pH maintenance prevents corrosion and scale formation.
• Chlorine residual monitoring in municipal drinking water distribution, leveraging ORP as a surrogate indicator for disinfectant efficacy (per US EPA guidance).
• Electroplating and anodizing bath management, where ORP stability directly correlates with metal ion oxidation state and coating uniformity.
• Food-grade CIP (clean-in-place) cycle verification, ensuring alkaline and acidic rinse phases meet defined pH thresholds before equipment reuse.
• Biological wastewater treatment, supporting nitrification/denitrification control through coordinated pH and ORP trending.

FAQ

Does the JENCO 3675 support automatic calibration?
No—it requires manual calibration using standard buffer solutions (e.g., pH 4.01, 7.00, 10.01) and redox standards (e.g., quinhydrone, Zobell’s solution). Auto-calibration is not implemented.
Can the 4–20 mA output be assigned to ORP instead of pH?
Yes—the output channel is user-selectable between pH, ORP, or temperature signals during setup.
Is the device suitable for high-pressure or submersible installation?
No—it is rated for ambient panel-mount use only; sensor cables must be routed separately to pressurized or submerged measurement points.
What is the recommended calibration frequency under continuous operation?
For critical applications, daily verification is advised; for stable processes, weekly two-point pH calibration and ORP zero-check suffice per ISO 5725 repeatability guidelines.
Does the unit store calibration data across power cycles?
Yes—calibration coefficients and relay configurations are retained in non-volatile memory without battery backup.