Hach SC200 Universal Process Controller

Overview

The Hach SC200 Universal Process Controller is an engineered platform for continuous, multi-parameter monitoring and control in demanding industrial water and wastewater applications. Designed around a dual-input architecture, it natively supports both Hach’s proprietary digital sensors (e.g., IntelliCAL™ pH, ORP, conductivity, dissolved oxygen, turbidity, chlorine) and legacy analog sensors (4–20 mA, 0–20 mA, mV) — eliminating the need for separate dedicated controllers. Its modular firmware allows field-configurable input assignments: two digital inputs, one or two analog inputs, or mixed-mode operation (e.g., one digital pH sensor + one analog conductivity transmitter). This flexibility enables phased system upgrades, sensor redundancy, and future expansion without hardware replacement. The controller operates on proven electrochemical and optical measurement principles — including glass electrode-based potentiometric pH sensing per ASTM D1293 and ISO 10523, and temperature-compensated current-loop signal interpretation for analog transmitters — ensuring traceable, repeatable process data under variable environmental conditions.

Key Features

• True universal input architecture: Configurable for dual digital, dual analog, or hybrid sensor configurations via intuitive menu navigation.
• Two independent 4–20 mA outputs supporting primary and auxiliary measurements (e.g., pH + temperature, or pH + ORP) with user-defined scaling and fail-safe behavior.
• Four programmable SPDT relays rated at 5 A / 250 VAC for pump control, alarm staging, or valve actuation — configurable with hysteresis and delay timers.
• Graphical LCD interface (240 × 160 pixels) with LED backlight and reflective-transmissive mode for readability in direct sunlight or low-light enclosures.
• Password-protected SD card slot (FAT32 formatted) enabling secure, audit-ready data export — compatible with Hach’s LogBook™ software for trend analysis and regulatory reporting.
• NEMA 4X / IP66-rated polycarbonate-and-metal enclosure suitable for outdoor, washdown, and corrosive environments; certified for wall, pole, or panel mounting.
• Comprehensive power resilience: Operates across 100–240 VAC or 24 VDC inputs with brownout tolerance and internal flash memory retention during power loss.

Sample Compatibility & Compliance

The SC200 interfaces with Hach’s full portfolio of online analytical sensors, including but not limited to: IntelliCAL™ pH/ORP sensors (e.g., PHC101, ORP101), CL17sc and CL17d chlorine analyzers, GLI 5500-series conductivity cells, and TU5 Series turbidimeters. It accepts third-party analog sensors compliant with IEC 60359 and NAMUR NE43 standards. All sensor configurations support automatic calibration recognition (for digital sensors) and manual span/zero adjustment (for analog units). The platform meets requirements for routine QC/QA documentation under EPA Methods 150.1 and 150.2, supports GLP-compliant data logging (with timestamped events, operator ID, and calibration history), and provides configurable audit trails aligned with FDA 21 CFR Part 11 when used with validated Hach software workflows.

Software & Data Management

Data handling is optimized for operational continuity and regulatory readiness. Internal flash memory stores up to 12 months of minute-interval data (configurable sampling intervals from 1 second to 24 hours). The SD card interface supports encrypted, time-stamped CSV exports with embedded metadata (sensor ID, calibration dates, alarm logs). When connected to Hach’s PlantWeb™ or DataStream™ infrastructure, the SC200 delivers real-time values and diagnostic status via MODBUS RTU over RS485 or Profibus DPV1 — enabling integration into DCS, SCADA, or MES platforms. Firmware updates are performed via SD card or serial connection, with version rollback capability and SHA-256 integrity verification. Configuration files are exportable/importable for fleet-wide consistency and backup recovery.

Applications

• Drinking water treatment: Continuous pH and chlorine residual monitoring at clearwells, booster stations, and distribution points.
• Wastewater influent/effluent monitoring: Dual-parameter control of pH and ORP in neutralization basins or disinfection contact tanks.
• Industrial process water: Closed-loop pH control in boiler feedwater, cooling towers, and chemical dosing systems.
• Food & beverage production: Sanitary pH monitoring in CIP rinse cycles and product stream validation.
• Pharmaceutical utilities: Conductivity and TOC-compatible pH verification in purified water (PW) and water-for-injection (WFI) loops per USP and EP 2.2.38.

FAQ

Can the SC200 simultaneously operate one digital pH sensor and one analog conductivity transmitter?
Yes — its hybrid input mode allows concurrent connection and independent configuration of one Hach digital sensor and one analog sensor (4–20 mA or mV), with separate scaling, alarms, and output assignments.
Does the SC200 support HART communication?
No — it does not interpret HART protocol signals. It accepts only native analog current/voltage inputs or Hach’s digital sensor protocol (DSP). For HART-enabled devices, a separate HART-to-MODBUS converter is required.
Is the SD card slot compatible with industrial-grade cards?
Yes — Class 10 microSDHC cards (up to 32 GB) are supported. Hach recommends industrial-temperature-rated cards (-40 to 85 °C) for extended outdoor deployment.
How is calibration data secured and auditable?
All calibrations are logged with date/time stamp, operator ID (if entered), sensor serial number, slope/mV offset, and buffer values. Logs are retained in flash memory and exported via SD card in uneditable CSV format.
What safety certifications apply to hazardous area installations?
The SC200 itself is not intrinsically safe or explosion-proof rated. It is intended for use in non-hazardous locations (Class I, Division 2 per NEC Article 500 requires external barriers if interfacing with field devices in classified zones).