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Online Analysers & Instrumentation

Online analysers are the eyes of a water treatment plant. pH, ORP, COD, TSS, ammonia, turbidity, chlorine and flow instruments provide continuous, real-time measurement that feeds closed-loop control and SCADA trending. Get the analyser, its placement and its upkeep right and the whole plant runs tighter; get it wrong and every control loop downstream inherits the error.

The Core Online Analysers

Continuous, real-time data with a 4–20 mA (or digital) signal to the PLC.

pH / ORP

Glass-membrane and redox probes for neutralisation, oxidation and disinfection control. Weekly calibration; 12–24 month electrode life.

Turbidity / TSS

Surface-scatter and ratio turbidimeters with auto-clean wipers for coagulation and clarifier performance.

COD / TOC

UV or wet-chemistry organic-load monitoring for load balancing and consent reporting.

Ammonia / nitrate

Ion-selective and wet-chemistry nutrient analysers for biological process and breakpoint control.

Chlorine residual

Amperometric or DPD residual measurement for disinfection control and CT compliance.

Flow

Electromagnetic and ultrasonic flow meters — the master signal for flow-paced dosing and mass balance.

Selection, Placement & Upkeep

An analyser is only useful if it reads true, representative and on time.

  • Representative location — well-mixed cross-section, after the reaction/contact zone
  • Low dead-time — close to the process so control stays stable (see dead-time)
  • Auto-clean on fouling-prone streams — wipers, air-blast or retractable mounts
  • Grab-sample tap adjacent for calibration verification
  • Calibration discipline — scheduled, logged, traceable

Signal to the PLC

4–20 mA, Modbus or HART signals feed the PLC for closed-loop control and the SCADA dashboard for trending and alarms.

A drifting analyser misleads control

A fouled probe reading low silently drives over-dosing; an accuracy audit catches it — see quality auditing.

Related Pages

Specify the right online monitoring

Tell us your process and consent parameters and we will specify the analysers, place them for representative, stable control, and integrate them into your PLC and SCADA with calibration and maintenance built in.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.