Overview

The industrial pH/ORP meter (hereinafter referred to as the instrument) is a microprocessor-based online water quality monitoring instrument. This instrument is equipped with different types of pH (or ORP) electrodes and is widely used in various industries such as power plants, petrochemicals, metallurgy, electronics, mining, papermaking, bio-fermentation processes, pharmaceuticals, food and beverage, and environmental water treatment for continuous monitoring and control of the pH (acidity/alkalinity) or ORP (oxidation-reduction potential) and temperature values ​​of aqueous solutions. Applications include power plant makeup water, saturated water, condensate, general industrial water, domestic water, and wastewater.

The instrument features an LCD display screen; intelligent Chinese menu operation; two current outputs; freely adjustable measurement range; high/low over-limit alarm prompts; two sets of relay control switches; adjustable hysteresis range; automatic cleaning switch setting; automatic or manual temperature compensation; and multiple automatic electrode calibration methods.

According to user needs, various installation methods for pH (or ORP) electrodes are available, including flow-through, submersible, pipeline, and flange types.

Structural Features and Working Principle

2.1 Working Principle

The instrument consists of signal measurement, calculation, display, network communication, and panel commands. The impedance conversion of the pH and temperature transmitters transforms the pH signal into a low-resistance signal of 59.16mV/pH (25°C); the NTC signal is converted into a voltage signal. The instrument is paired with a pH (or ORP) electrode to monitor the pH (or ORP) value of a solution. The sensor is a battery consisting of a pH (or ORP) glass electrode and a calomel (or Ag/AgCl) reference electrode. It generates a potential difference related to the solution's pH value based on the Nernst equation: Ex = Eo + SpH. This potential difference is amplified by a preamplifier with high input impedance. A thermistor outputs a signal corresponding to the temperature value. Both signals are amplified, converted to digital (A/D) values, processed by a microprocessor via an I/O interface chip, and then displayed prominently on the screen.

Technical Parameters

(1) Measurement Range: pH: 0.01~14.00pHOR: -1999~+1999mV; Temperature: -5~110.0°C;

(2) Resolution: pH: 0.01pH; ORP: 1mV;
(3) Basic Error: pH: ±0.1pH; ORP: ±3mV; Temperature: ±0.5°C;

(4) Automatic or Manual Temperature Compensation Range: -10~110°C;

(5) Stability: pH: ≤0.02pH/24h; ORP: ≤2mV/24h;(6) Signal Output: 4~20mA+HART (Load resistance <7500Ω, optional)
(7) Power supply: 24VDC, power ≤1W;

(8) Dimensions: 130X107X134mm;

(9) Installation method: Panel mounting (embedded) and wall-mounted; Opening size: 91X91mm;

(10) Wall-mounted: Waterproof wall-mounted box size: 300 (height) X200 (width) X167 (depth) m;

(11) Instrument weight: 1.2kg;

(12) Working environment: Ambient temperature: -10~60°C;

Relative humidity: not greater than 90%;

No strong magnetic field interference in the surrounding area except for the Earth's magnetic field.

Functional Characteristics
*Intelligence: Employs a single-chip microprocessor to complete pH (or ORP) measurement, temperature measurement, and compensation;
*Dual High-Impedance Preamplifiers: High input impedance, noise reduction, and strong anti-interference capability;
*Three calibration methods: one-point calibration, two-point calibration, and known concentration calibration; Human-Machine Interaction: Menu-driven operation; users can operate by following the on-screen prompts.

Software Output Setting: Software allows selection of 0~10mA or 4~20mA output.

After-Sales Service: Provides technical support and after-sales service contact information.

Two-wire 24V power supply; easy wiring and convenient use.