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pH Controller Range
The AWE Direct pH controllers are available in two different varieties which can be split into either a Surface Mounted pH Controller or a Panel Mounted pH controller. All of our pH instruments in our panel mounted pH controller range are available in an optional enclosure for Surface Mounted pH Controller configuration. The surface mounted instruments are denoted with a -W, so the P7635-W is surface mounted where the P7635 is panel mounted.
The AWE Instruments pH controller range is designed to offer instruments for use as either "stand-alone pH control units" or as part of a larger system.
Measuring pH using a pH Electrode
For increased accuracy and precision measurement of pH, we recommend that you pair your pH instrument with a pH electrode from our range. Each of our controllers are designed to work with any of the probes within the range, and we offer pH electrodes for all installation types including industrial pH probes, laboratory pH electrodes, inline pH sensors, and insertion pH electrodes.
Automated pH adjustment and pH correction
Each of our pH controllers include control relays for the control of your application. These can be broadly split into the following types: pH Controller with On / Off control relays.
The P7635, P7335, P3647 and MO5 range of instruments are fitted with 2 On / Off control relays.
Within the instrument a pH value can be assigned as a setpoint (such as a value of 7.00pH). When the pH value is below this point, a control relay will switch allowing a dosing pump to activate or a normally closed solenoid valve to open. When the set point value is reached the control relay will switch again to stop the dosing pump from operating or to return the solenoid valve to closed. In this instance, the On / Off control relay is set to low. Because each instrument includes at least 2 x control relays, the pH Value of the second control relay can be assigned another value. For example, this value could be set at 10.00 pH. If the pH is above this value, a second dosing pump or solenoid valve could be controlled to dose an acid to reduce the pH value below the setpoint. This second On / Off control relay would be set to high.
pH Controller with Proportional Control Relays (PFM or Pulse Frequency Modulation)
Our models P7685.010 and P7685 can both be classed as including proportional control relays. They both include 2 x control relays which can offer PFM control (Pulse Frequency Modulation) or the user can select them to operate with PWM control (Pulse Width Modulation). The Pulse Frequency Modulation or PFM relays allow for the proportional control of our of dosing pumps. By controlling the dosing pumps in this way, the amount of chemical dosed can be precisely controlled; increasing the efficiency and reducing the amount of chemical used. In addition, the pH can also be more precisely controlled. A typical installation could be for a pH correction system for effluent discharge. This is very effective considering the logarithmic nature of the pH scale. (Significantly less chemical is required to correct the pH from a value of 6.00pH to 7.00pH than is required to change the pH from 3.00pH to 4.00pH), and is often used in process control or where a consent to discharge agreement is in place.
pH Controller with Proportional Control Relays (PWM or Pulse Width Modulation)
Our P7685.010 and P7685 pH controllers can be used with either one or both of their relays acting as PWM control relays. (Pulse Width Modulation Relays).
The MO5 pH controller can use one of its 3 control relays as a PWM Control relay for the proportional control of solenoid valves.
The PWM or Pulse Width Modulation relays are designed for use with our range of solenoid valves. The pulse width modulation acts in a similar way to how the pulse frequency modulation relays work with our metering pumps. The PWM relays allow a solenoid valve to stay open for a defined period of time, regulating the flow of a reagent proportional to the measured pH value. Typically PWM relays control solenoid valves which allow the discharge of lime or caustic as a reagent. The P7685, P7685.010, and MO5-pH range of instruments can use a 4-20mA output for the proportional control of dosing pumps or to output the signal across the full 0.00 - 14.00 pH range, for use with a recorder, videograph, datalogger, PLC or other device.
Please note that the P7635, P7335 and P3647 can only use the 4-20mA across the full 0 - 14.00 pH for digital chart recorder, data logger or PLC applications. It cannot use the 4-20mA output for proportional control of our dosing pumps.
pH Controller Range
P3647
The P3647 is an easy to use pH controller offering precise pH measurement and control options and has two control relays.
The built in control relays are able to operate using on / off control functionality and can be set to high or low pH for the dosing of either acids or caustic.
Operated from a mains volutage the P3647 is easy to calibrate with a simple adjustment of the zero and span to continue offering accurate pH measurements and control options all in a simple surface mounted enclosure.
P7335
The P7335 is a powerful pH controller in compact sized casing.
Offering precision measurement and a bright LCD (liquid crystal display) the P7335 offers 2 control relays with on / off control, an isolated 4-20mA output and simple 4 push button operation for setup and calibration.
The P7335 is user selectable for either pH or Redox measurements
P7635
The P7635 is a pH controller with 2 control relays and isolated 4-20mA output and is ideal for panel mounting.
Also available in surface mounting configuration the P7635 offers 2 control relays which can be set to high or low set points, an alarm set point of the instrument is out of the desired pH range and an isolated 4-20mA output to integrate with a PLC or datalogger.
The P7635 has 8 front mounted push buttons for easy calibration and configuration and is user selectable for either pH or Redox measurements
P7685
The P7685 panel mounting pH controller is a feature packed instrument designed for precision measurement and control of pH in a process.
With 2 x set-points and associated control relays, the P7685 can operate in either PFM (Pulse frequency modulation) mode to proportional control a dosing pump or PWM (Pulse width modulation) mode for proportional control of solenoid valves.
The P7685 also offers proportional control through an invertible and expandable 4-20mA control signal which can be connected to compatible control equipment such as dosing pumps or actuated valves.
There are plenty more features and functions within the P7865 too - visit the product page for more information. The P7685 is user selectable for either pH or Redox measurements
P7685-010
The P7685-010 is a combination instrument building on the P7685 by adding the option to precisely measure and control pH, Redox and Temperature.
The P7685-010 is a dual input device and includes 2 x 4-20mA outputs relating to pH, Redox or Temperature.
The P7685-010 incorporates an auto clean relay which can be used to clean pH probes automatically.
The set points can be On / Off, or PWM / PFM for proportional control. The dual 4-20mA outputs are also expandable and invertible for precision control of processes and effluent treatment.
P7687
The P7687 pH controller is a panel mounting controller with dual isolated 4-20mA outputs, control relays and an alarm relay.
Suitable for use with either a pH electrode, Antimony pH Electrode, with automatic temperature compensation, the P7867 will also operate from a Redox mV Electrode.
A sophisticated control instrument - the P7687 offers on / off control, proportional control from PFM or PWM control relays, or can operate using full PID (Proportional, Integral and Derivative) control specifically designed for the logarithmic nature of pH.
P6587
The P6587 pH controller is a surface mounting pH controller designed to IP65 specifications for indoor or outdoor usage.
Inside the surface mounted controller the P6587 offers dual isolated 4-20mA outputs, control relays and an alarm relay.
Suitable for use with either a pH electrode, Antimony pH Electrode, with automatic temperature compensation, the P6587 will also operate from a Redox mV Electrode.
A sophisticated control instrument - the P6587 offers on / off control, proportional control from PFM or PWM control relays, or can operate using full PID (Proportional, Integral and Derivative) control specifically designed for the logarithmic nature of pH.