Digital pH Controller Online – 2 Set Point pH Controller with Dual Relay Output

Uma Industries (Machine Control Systems) manufactures and supplies a
Digital pH Controller Online for accurate pH monitoring and automatic
dosing pump / alarm control in industrial applications.
This panel mounted controller is designed for continuous 24×7 operation in
ETP/STP plants, RO water treatment, chemical dosing systems, pharma, food and other process industries.

Unlike a pH meter that only displays the pH value, a pH controller measures pH
and also provides control outputs (relays) to automatically switch dosing pumps or alarms
ON/OFF when the pH crosses preset limits. With two independent set points (low and high),
this model supports better neutralisation control and reduces chemical wastage.

Digital pH Controller Online

• Online digital pH controller for continuous 24×7 process monitoring
• Two independent set points – Low pH and High pH limits
• Two potential-free (dry contact) relay outputs for dosing pumps / alarms
• Separate relay action for low pH and high pH conditions
• Easy operation using SET, UP, DN and ENT front panel keys
• 2-point calibration using pH 4.00 and pH 7.00 standard buffers
• Bright 7-segment LED display for clear visibility in industrial environments
• Panel mounted enclosure suitable for electrical control panels

How the Controller Works (Low & High pH Control Logic)

The controller continuously measures pH using a standard pH electrode.
When the measured pH crosses the preset set points, the corresponding relay output activates
to control a dosing pump, valve or alarm. This maintains pH within a safe operating range.

Low pH Set Point (Relay 1)

• Activates when process pH goes below the low set value
• Used for alkali dosing, low-pH alarm, or safety interlock (as per wiring)

High pH Set Point (Relay 2)

• Activates when process pH goes above the high set value
• Used for acid dosing, high-pH alarm, or safety interlock (as per wiring)

Technical reference:

pH measurement principle

Set Point Adjustment Procedure

Set High pH (Relay 2)

1. Press the SET key once.
2. The high set value will blink on the display.
3. Adjust the value using UP / DN keys.
4. Press ENT to save.

Set Low pH (Relay 1)

1. Press the SET key twice.
2. The low set value will appear on the display.
3. Adjust the value using UP / DN keys.
4. Press ENT to save.

With these two set points, the controller can automatically control two dosing pumps (acid/alkali)
or two alarms for precise pH control in industrial dosing lines and neutralisation tanks.

Calibration Procedure | Digital pH Controller Online

1. Rinse the pH probe with distilled (DM) water.
2. Place it in pH 7.00 buffer and adjust the 7.00 calibration screw until stable.
3. Rinse the probe again with DM water.
4. Place it in pH 4.00 buffer and adjust the 4.00 calibration screw until stable.
5. Repeat once if needed to confirm accuracy.

Technical Specifications – Digital pH Controller

• Range: 0.00 to 14.00 pH
• Resolution: 0.01 pH
• Calibration: 2-point (pH 4.00 & 7.00), front panel adjustment
• Input: Standard pH probe / electrode (BNC connector)
• Set Points: 2 (Low & High)
• Outputs: 2 × potential-free relay outputs (dosing pump / alarm control)
• Display: Bright 7-segment LED
• Power Supply: 220–230 V AC
• Panel Size: 96 × 96 × 85 mm (panel mounted)
• Body: PP / ABS

Typical Applications

• Effluent Treatment Plants (ETP)
• Sewage Treatment Plants (STP)
• Neutralisation tanks and chemical dosing skids
• RO feed water conditioning
• Cooling tower and boiler water treatment
• Textile dyeing and processing
• Electroplating & surface treatment plants
• Food, beverage and pharmaceutical utilities

Why Choose Uma Industries? | Digital pH Controller Online

Uma Industries is a trusted Indian manufacturer of online pH controllers and process instrumentation.
Our controllers are designed for industrial conditions, provide stable relay control and are easy to calibrate.
We also provide technical guidance, spare parts support and supply across India for OEMs, dealers and end users.

Related Products

• Digital pH Meter Online – Panel Mounted
• Modbus 485 pH Meter Online – RS-485 Modbus RTU
• RS-485 Modbus RTU pH Controller
• Table-Top / Portable Laboratory pH Meter
• pH Sensor / Probe / Electrode

Price & Enquiry

For price, quotation, datasheet, bulk supply or dealership enquiry,
contact Uma Industries. Share your application details (ETP, STP, dosing tank,
pipeline process) and we will recommend the suitable pH controller model.

Call / WhatsApp:
+91-8178668698