A pH sensor (electrode) measures the acidity or alkalinity of a liquid, and a pH transmitter (meter or controller) converts the sensor signal into a displayed value and standard output signals. Together they are used for online pH monitoring and control in chemical, metallurgy, environmental protection, food, agriculture and water treatment applications.

The pH sensor detects the activity of hydrogen ions in the solution through a glass electrode and generates a small potential signal. The pH transmitter amplifies this weak signal, applies temperature compensation and linearization, and converts it into a standard electrical output for display, control or remote transmission.

pH indicates hydrogen ion activity (acidity or alkalinity), while ORP (oxidation-reduction potential) indicates the oxidizing or reducing ability of a solution, measured in mV. ORP is often used to monitor disinfection and oxidation or reduction processes. Many Asmik transmitters support both pH and ORP, and the MIK-ORP6050 is a dedicated ORP sensor.

For analog pH electrodes, yes: the electrode provides the measurement signal and the transmitter displays it and provides outputs. A digital sensor such as the MIK-PH8001 has a built-in RS485 Modbus RTU interface and can communicate directly with a PLC, data logger or IoT system.

• MIK-PH6.5, MIK-PH6.8 and MIK-PH8.0: online pH/ORP meters with 4–20 mA, RS485 and relay outputs for industrial and water treatment pH control
• MIK-PH163S: online pH/ORP meter with 4–20 mA, RS485 and relay outputs, supporting remote data transmission
• MIK-DC-P2: dual-channel controller; the first channel accepts analog or digital sensors, the second connects digital sensors
• MIK-DC2000: universal analyzer monitor supporting pH, ORP and other parameters

If you are unsure, send us your application details and our engineers will recommend a model.

• MIK-pH6001 plastic body: general industrial use and challenging environments
• MIK-pH6002 glass body: laboratory and industrial use
• MIK-PH7001 flat pH sensor: flue gas desulfurization (FGD) and harsh media such as lime slurry
• MIK-PH5013A PTFE: corrosive media
• MIK-PH5014: water containing hydrofluoric acid
• MIK-PH5022: high-quality combined electrodes for professional process measurement
• MIK-PH8001 digital sensor: aquaculture and IoT water quality monitoring with RS485 output

An analog sensor outputs a small millivolt signal that must be connected to a pH transmitter, usually with a limited cable length. A digital sensor converts the measurement inside the sensor and communicates via RS485 (Modbus RTU), which is less sensitive to interference and makes it easy to connect multiple sensors to one system.

Yes. Standard glass membranes can be attacked by hydrofluoric acid. The MIK-PH5014 uses a pH-sensitive glass membrane resistant to hydrofluoric acid, and is used for pH measurement in water containing hydrofluoric acid and for dilution control of hydrofluoric acid in semiconductor wafer and chip manufacturing.

The MIK-PH7001 flat pH sensor is designed for FGD and other harsh environments, such as lime slurry. Its flat sensing surface helps reduce fouling and damage in slurry applications.

The electrode response changes with temperature, so the same pH value produces a different signal at different temperatures. Temperature compensation corrects for this effect, and Asmik pH transmitters support temperature compensation for more accurate readings.

pH sensors are calibrated with standard buffer solutions. Asmik standard pH calibration solutions are available in common sets of 4.00, 7.00 and 10.00, or 4.00, 6.86 and 9.18, with an accuracy of ±0.01 pH at 25 °C, and are dyed in different colors for easy identification. Choose buffers that bracket your process pH range and follow the calibration procedure of your transmitter.

Calibration frequency depends on the application, process conditions and required accuracy. Sensors in dirty or aggressive media generally need more frequent checks. A common practice is to check the reading regularly against a buffer or reference measurement and recalibrate when the deviation exceeds your tolerance.

A pH electrode is a consumable component. Its service life depends on the medium, temperature, cleaning and storage conditions. Aggressive chemicals, high temperatures, abrasive slurries and letting the electrode dry out generally shorten its life.

• Keep the glass membrane wet; do not let it dry out.
• Store the electrode with its protective cap and storage solution when not in use.
• Clean the electrode regularly according to the type of contamination.
• Avoid touching or scratching the glass membrane.
• Recalibrate after cleaning.

Please follow the manual of your electrode for recommended storage and cleaning solutions.

Asmik offers pH installation accessories, including a pH installation box, installation bracket and pH signal amplifier for sensor and controller installation.

Yes. Asmik online pH meters provide relay outputs that can be used for pH control, for example to start or stop dosing pumps. The 4–20 mA and RS485 outputs can also send pH values to a PLC or control system. See our metering pumps for dosing.

Yes. The MIK-ADS2000 COD sensor is based on the UV absorption principle. It requires no reagents, causes no secondary pollution, and has an integrated self-cleaning brush.

Typical industries include chemical, metallurgy, environmental protection, water and wastewater treatment, food, agriculture, aquaculture, power plant flue gas desulfurization and semiconductor manufacturing.

To help us select the correct model, please provide:

• Application and medium (e.g., wastewater, slurry, acid, pure water)
• pH range, temperature and pressure
• Special components (e.g., hydrofluoric acid, solids, oils)
• Installation method (immersion, flow-through or pipe insertion)
• Analog or digital sensor, and cable length
• Transmitter outputs (4–20 mA, RS485, relay) and power supply
• Whether ORP or other parameters are also required
• Quantity

Send your requirements to info@asmik.com or contact us via WhatsApp at +86 13325716921.