Measures DO (ppm) and temperature
Sensor suitable for waste water applications, with built-in preamplifier
Automatic temperature compensation
Set point with adjustable dead band and time delay
Voltage and current (4‑20 mA) analog output
The DO 231 controller is a precision instrument, suitable for measurement and control of the dissolved oxygen (DO) concentration in industrial applications.
Typical areas of application are :
- biological waste water treatment plants (urban and industrial)
- public waters (rivers, lakes and reservoirs)
- fish farming in fresh and salt water
- industrial water treatment
The basic DO control system consists of :
Panel mounting instrument, type DO 231, placed in a flame retardant plastic enclosure (96 x 96 mm, according to DIN43700),
The system can measure dissolved oxygen concentration from 0 to 20 ppm and temperature from 0 to 50°C, compensating the DO reading automatically for temperature changes in the process.
The DO 231 controller provides a switching control output (relay contact). The set point can be accurately adjusted at any value within the measuring range and functions as a "hi" or "low" limit to the control process, with adjustable dead band and time delay on the activation of the output control signal.
The analogue output section of the DO 231 provides voltage (+100mV/ppm, +10mV/°C) and current (4-20 mA) outputs - non isolated. So the instrument can be connected to a recorder, PLC (via an A to D device) or auxiliary control devices such as the unit PL 201 (for additional set points), extending the control capabilities of the system and offering the ideal solution for almost any dissolved oxygen control application.
The DO 231 controller may be used with the DO and temperature transmitter type CH 232 ( I or T ). The dissolved oxygen measurement is based on a polarographic sensor type IDC31 with interchangeable membrane module.
These dissolved oxygen sensors with a built-in preamplifier are ideal for almost every industrial application. The robust construction and the sensor design provide :
- Extra long service life (several years).
- No need for frequent recalibration.
- Reliable operation under severe conditions.
- Sensor installation at a distance up to 200m from panel instrument
- Convenient mounting in tanks and reservoirs (type I) or on pipe networks in series or by pass (type T) and easy connection with the panel instrument, using a single cable.