Rugged and reliable pH/ORP analyzers/controllers.


  • Measures and controls pH, ORP and temperature
  • Easy to setup and calibrate
  • 5 programmable relays: 2 for pH, 2 for ORP and 1 for temperature
  • Isolated and reversible 4 to 20 mA output for a single parameter

pH/ORP Controllers Product Description

The Global Water 6309POT multiparameter pH/ORP Controller measures, analyzes, and controls pH, ORP and temperature in one easy to use unit. The pH/ORP Controller’s setup and calibrations are done through a user-friendly menu that may be password protected. Calibrations can be performed quickly and accurately with automatic buffer recognition of U.S. or European buffer sets, with the values stored in the pH/ORP Controller’s nonvolatile memory. A large backlit display on the pH/ORP Controllers provide pH, ORP, and temperature plus the current mA output and relay status.

The WQ250 multiparameter pH/ORP controllers provide accurate on/off control via the five programmable relays or the 4 to 20 mA output may be used for proportional control. A standard RS-485 output allows for remote access via PC compatible computer and makes it possible to link multiple pH/ORP controllers to a common control system. The pH/ORP controllers built-in temperature and Automatic Temperature Compensation (ATC) functions may be used with an ATC type sensor or with a 10K ohm thermistor.

At power up, the WQ250 pH/ORP controllers perform a self-diagnostic to ensure proper operation. pH/ORP controllers electrode efficiency can be displayed to indicate when electrode maintenance is necessary. Housed in a watertight (IP65), ¼ DIN case, the 6309POT pH/ORP controllers include a terminal block that accommodates the tinned leads and spade lugs on industrial type pH and ORP electrodes.

NOTES: A BNC to Y adapter is required to maintain the IP65 rating when using sensors with a BNC connector. A signal amplifier is required for sensor cable runs over 40 feet.

pH/ORP Controllers Specifications

Temp Compensation: Auto 14.0 to 248.0 °F (-10.0 to 120.0 °C)
Buffer Recognition: 4.00, 4.01, 6.86, 7.00, 9.18, 10.01
Buffer Temperature Range: 32 to 140 °F (0 to 60 °C)
Electrode Offset Recognition: ± 100 mV at pH 7.00 – 91.7 to +108.3 at pH 6.86
Electrode Slope Recognition: ± 30 % at pH 4.00, 4.01, 9.18 or 10.01
Input Impedance: >1013 ohms
Calibration End Point Sensing: Yes
Temperature Sensor: Thermistor, 10.00 k ohm at 77deg F (25 °C)

4-20 mA Analog Output:
Input Select: User selectable pH or ORP
Current Output Range: 4 to 20 mA (isolated), programmable span
Current Output Scale: User programmable, linear or log
Maximum Load: 500 ohm
Accuracy: ± 0.02 mA
Isolation Voltage: 500 V DC

Control Type: 5 ON/OFF controls
Relay Output: 5 A at 115 V AC or 2.5 A at 220 VAC, resistive load only

Power Supply: 115 V AC or 230 V AC at 50/60 HZ
Communication: RS-485
Display: 128 x 64 graphical LCD with backlight
Ambient Temp. Range: 0 to 122 °F (0 to 50 °C)
Case: IP65, 1/4 DIN case, 5.83 inch (148 mm) depth
Dimensions: 3 5/8″W x 3 5/8″H x 5 7/8″D (96 x 96 x 148 mm)
Weight: 2.1 lb (950 g)
Certifications: CE, ISO 9001:2000

pH/ORP Controllers Options

6309POT pH/ORP Controller (PN# HB0500)
Industrial pH/ORP Controller sensor not included.


WQ220-020 pH/ATC Controller Electrode (PN# HB0610)
20 FT w/Spade & Tinned Leads

WQ620-020 ORP Controller Electrode (PN# HB0630)
20 FT w/Spade & Tinned Leads


600B-Y Adapter (PN# HB0700)
BNC Connector to Spade Lugs & Tinned Leads


ORP15A Handheld ORP Meter

695ORP Industrial ORP Transmitter (PN# DO0500)
(ORP sensor not included)

WQ600 ORP/Redux Sensors (PN# DE0000)

PC320 pH Controller

WQ Water Quality Sensors