Modbus 485 pH Meter Online – RS-485 Digital pH Meter for PLC & SCADA

Uma Industries & Machine Control Systems (MCS) manufacture and supply
Modbus 485 pH Meter Online models for continuous 24×7 industrial pH monitoring.
This panel mounted digital pH meter is designed for reliable operation in harsh environments
and for integration with PLC, HMI and SCADA systems using RS-485 Modbus RTU communication.

It is ideal for applications such as ETP/STP plants, RO & DM water treatment,
chemical dosing and neutralisation processes, process industries, pharma,
food & beverage, electroplating, cooling tower water and boiler water monitoring.
If you need an online pH meter with stable readings and automation connectivity,
this model offers simple calibration, rugged construction and dependable communication.

Key Features of Modbus 485 pH Meter Online

• Panel mounted industrial design (fits standard 96 × 96 mm panel cut-out)
• RS-485 Modbus RTU communication for PLC / HMI / SCADA / data logger
• Continuous online pH monitoring for 24×7 process control
• 2-point calibration using pH 4.00 and pH 7.00 buffer solutions
• Front-panel calibration controls for easy field adjustment
• Bright 7-segment LED display for clear visibility
• BNC input compatible with standard pH probes / electrodes
• Heavy-duty PP / ABS enclosure for industrial environments

Technical Specifications

• Measurement Range: 0.00 to 14.00 pH
• Resolution: 0.01 pH
• Calibration: 2-point (pH 4.00 & 7.00)
• Input: pH probe / electrode (BNC connector)
• Display: Bright 7-segment LED
• Communication: RS-485 Modbus RTU
• Power Supply: 220–230V AC, single phase
• Enclosure: 96 × 96 × 85 mm (panel mounting)
• Application: Industrial online pH measurement with Modbus communication

Working Principle of Modbus pH Meter

The pH value represents the concentration (activity) of hydrogen ions (H⁺) in a solution.
When a pH electrode is immersed in the process liquid, a small millivolt potential is generated
across the glass membrane due to the difference in hydrogen ion activity between the process solution
and the internal reference solution inside the electrode.

The digital pH meter measures this potential, calculates the pH value using the Nernst equation,
displays the pH on the front panel and transmits the reading digitally over
RS-485 Modbus RTU to your PLC/SCADA system.

• pH < 7 – Acidic solution
• pH = 7 – Neutral solution
• pH > 7 – Alkaline solution

Technical reference:

pH measurement principle


pH measurement principle

Calibration Procedure

1. Rinse the pH electrode gently with distilled (DM) water.
2. Immerse the probe in pH 7.00 buffer and allow the reading to stabilise.
3. Adjust the front-panel 7 pH calibration control.
4. Rinse the probe again with DM water.
5. Immerse in pH 4.00 buffer and adjust the 4 pH control.
6. Repeat once to confirm calibration accuracy.

Regular calibration helps maintain accurate process control, reduces chemical consumption and
ensures reliable Modbus data transmission to automation systems.

Why Choose Modbus 485 pH Meter Online from Uma Industries?

Uma Industries is a trusted Indian manufacturer of industrial pH meters and process instrumentation.
Our Modbus pH meters are engineered for long-term stability, dependable RS-485 communication and easy maintenance.
We provide application guidance, calibration support, spare parts availability and pan-India delivery
for OEMs, integrators and industrial customers.

Typical Industrial Applications

• Effluent Treatment Plants (ETP) & Sewage Treatment Plants (STP)
• RO & DM water treatment systems
• Chemical dosing and neutralisation systems
• Process industries (chemical, textile, engineering)
• Food & beverage processing utilities
• Pharmaceutical and biotech plants
• Electroplating and surface treatment industries
• Cooling tower and boiler water monitoring

Related pH Meters and Controllers

• 
  Digital Online pH Meter – Panel Mounted
  
• 
  Online pH Meter with 0–10 V Output
  
• 
  Online pH Meter with 4–20 mA Output
  
• 
  RS-485 Modbus RTU pH Controller
  
• 
  Laboratory Table-Top / Portable pH Meter
  
• 
  pH Sensor / Probe / Electrode
  

Price, Quotation & Dealer Enquiry

For price, quotation, bulk orders, OEM supply or dealership enquiries,
contact Uma Industries. Share your application details and automation requirement
(PLC / SCADA / data logger), and we will recommend the most suitable Modbus pH meter model.

Call / WhatsApp:
+91-8178668698