Huake Instrument HK-328W Online Wastewater pH Analyzer
| Brand | Huake Instrument |
|---|---|
| Model | HK-328W |
| Enclosure | Die-cast aluminum, ESD-safe |
| Display | 192 × 64 dot-matrix LCD (Chinese/English selectable) |
| pH Range | 0.00–14.00 pH |
| mV Range | −1000 to +1000 mV |
| Temperature Range | 0.00–99.9 °C (ATC: 0.1–60.0 °C) |
| pH Resolution | 0.01 pH |
| mV Resolution | 0.1 mV |
| Temp. Resolution | 0.1 °C |
| pH Accuracy | ±0.1 pH |
| Temp. Accuracy | ±0.5 °C |
| Output | Dual isolated 4–20 mA (or 0–10 mA / 0–20 mA), ±1% FS, load ≤800 Ω |
| Alarm Outputs | 2 relay outputs |
| Communication | RS485, Profibus DP, HART |
| Sample Temp. | 0.0–60.0 °C |
| Max. Sample Pressure | <0.6 MPa |
| Ambient Temp. | 5–60 °C |
| Humidity | ≤95% RH |
| Storage Temp. | −25–55 °C (electrode storage >0 °C) |
| Power | AC 100–240 V, 50–60 Hz |
| Power Consumption | 8 W |
| Dimensions | 158 × 158 × 170 mm (W×H×D) |
| Panel Cutout | 139 × 139 mm |
| Weight | 2 kg |
| Electrode Type | Wastewater-compatible triple-junction composite pH electrode (standard 10 m or optional 20 m cable) |
Overview
The Huake Instrument HK-328W Online Wastewater pH Analyzer is an industrial-grade process monitoring instrument engineered for continuous, reliable pH measurement in demanding wastewater and industrial effluent streams. It operates on the principle of potentiometric pH sensing using a robust triple-junction composite pH electrode, which minimizes liquid junction potential drift and resists clogging, sulfide poisoning, and organic fouling common in municipal and industrial wastewater applications. The analyzer features a die-cast aluminum housing rated for NEMA 4X equivalent environmental protection—offering inherent electrostatic discharge (ESD) safety, high electromagnetic interference (EMI) immunity, and long-term corrosion resistance in humid, chemically aggressive plant environments. Designed for wall, pipe, or panel mounting, the HK-328W integrates seamlessly into distributed control systems (DCS), programmable logic controllers (PLC), and SCADA architectures via standard industrial protocols.
Key Features
- Dual isolated 4–20 mA analog outputs with configurable range assignment (pH, mV, or temperature), enabling simultaneous transmission to control systems and data historians
- Two programmable relay alarm outputs with configurable hysteresis and latching/non-latching modes for process deviation alerts or pump interlocks
- Automatic temperature compensation (ATC) using integrated Pt1000 RTD input; supports manual temperature entry when external sensor is unavailable
- High-contrast 192 × 64 dot-matrix LCD display with bilingual (English/Chinese) interface—optimized for readability under low-light or high-glare conditions
- Embedded microcontroller architecture with surface-mount technology (SMT) PCB design, delivering enhanced thermal stability and long-term calibration retention
- Onboard non-volatile memory supporting ≥100,000 timestamped data points with user-accessible historical trend review (pH, temp., mV) via front-panel navigation
- Multi-protocol digital communication: RS485 (Modbus RTU), Profibus DP (V0/V1), and HART 7—ensuring interoperability with legacy and modern automation ecosystems
Sample Compatibility & Compliance
The HK-328W is validated for continuous operation in typical industrial wastewater matrices—including activated sludge effluents, chemical plant discharges, cooling tower blowdown, and refinery sumps—with operating temperature up to 60.0 °C and pressure tolerance below 0.6 MPa. Its triple-junction pH electrode incorporates a ceramic frit reference junction and gel-filled electrolyte system, significantly extending service life in suspended solids–rich media. While not certified to IEC 61508 SIL or ATEX/IECEx for hazardous areas, the analyzer complies with CE marking requirements (EMC Directive 2014/30/EU and LVD Directive 2014/35/EU) and meets RoHS 2011/65/EU material restrictions. For regulated environments, its data logging and configuration change audit trail support GLP-aligned documentation practices; however, native FDA 21 CFR Part 11 electronic signature compliance requires external validation of the host SCADA/HMI system.
Software & Data Management
No proprietary PC software is bundled; configuration and calibration are performed locally via intuitive front-panel menu navigation with password-protected access levels (operator, technician, administrator). All calibration events—including buffer recognition (pH 4.01/7.00/10.01), slope/mV offset verification, and ATC coefficient adjustment—are time-stamped and stored in non-volatile memory. Historical data export is supported via Modbus RTU polling by third-party historian platforms (e.g., Ignition, Siemens Desigo, or Emerson DeltaV). The device implements cyclic redundancy check (CRC) on all serial communications and includes watchdog timer supervision to ensure deterministic firmware recovery from transient faults.
Applications
- Real-time pH monitoring in primary and secondary wastewater treatment basins to optimize coagulant dosing and biological nitrification/denitrification
- Effluent compliance verification prior to discharge—supporting regulatory reporting under EPA NPDES permits or EU Urban Wastewater Treatment Directive (91/271/EEC)
- pH control loops in chemical dosing stations for neutralization of acidic/alkaline industrial discharges
- Process water quality assurance in power plant condensate polishing and boiler feedwater systems
- Monitoring of scrubber liquor pH in flue gas desulfurization (FGD) units within fossil-fuel power generation facilities
FAQ
What electrode types are compatible with the HK-328W?
The analyzer is factory-calibrated and optimized for Huake’s wastewater-specific triple-junction composite pH electrodes (model HK-WP3 series), available with 10 m or 20 m armored cable variants. Standard single-junction glass electrodes are not recommended due to rapid fouling and reference junction instability.
Does the HK-328W support automatic calibration?
No—it requires manual two-point or three-point calibration using certified NIST-traceable buffer solutions. Automatic calibration is not implemented per IEC 60746-2:2021 guidance for process analyzers in unattended installations.
Can the device operate in outdoor enclosures without climate control?
Yes, provided ambient temperature remains within 5–60 °C and relative humidity does not exceed 95% non-condensing. Extended exposure above 60 °C may accelerate LCD degradation and affect long-term zero stability.
Is HART communication fully functional with standard handheld communicators?
Yes—the built-in HART 7 stack supports universal commands (e.g., read device variables, perform loop test) and proprietary commands for calibration data retrieval and diagnostic status via any HART-compatible field communicator (e.g., Emerson 475, Yokogawa YHC5150).
