Controller designed for water treatment systems

Paul Boughton

Burkert's new mxControl multi-parameter controller automates the precise control of process variables within a water treatment system (boiler, cooling or reverse osmosis system) by integrating all the control, monitoring, display, and data and event logging functions into one compact, easy-to-configure controller.

 The mxControl accepts analogue inputs from flow, pH, temperature, level, analytical and conductivity sensors, and provides high-level computations to optimise the water treatment process. In addition, the controller delivers savings on time, space and equipment costs; one controller hardware specification provides dozens of configuration possibilities, all of which can be quickly downloaded via SD card (supplied) or a USB or optional Ethernet interface

The mxControl 8620 is claimed to be the first modular control system designed for seamless integration into chemical or skid control applications. The controller meets the dynamic and exacting requirements of water treatment systems in all sectors of industry, commerce, healthcare, public service and bio-medical. Employing high-level software, the controller provides the continuous on-line monitoring and process control required to achieve higher degrees of precision and improved reliability and quality assurance in today's demanding water treatment systems.

Burkert says the flexible control and easy adaptation to processes provided by the mxControl is the result of a high-level software architecture. This enables all standard modules to be easily loaded by SD card or USB. Alternatively, the optional Ethernet interface can be used to configure and to parameterise the controller, or an operator can simply set and display all important variables and parameters by five soft-touch keys. Once this is achieved, sophisticated electronics and state-of-the-art control algorithms ensure that optimum process control is maintained at all times, with the minimum of operator intervention. Moreover, operating security can be tailored to individual applications with three levels of man-machine interface available: open access, operator only access, or specialist access.

Key to this high-level, automated control provided by the mxControl is a 32-bit micro-controller. This is supported by an integrated 512kB flash memory for data logging or additional languages. In addition, an extended facility for data logging is provided by an SD memory card that simply slots into the controller.

What this processing power means for users is that the mxControl is able to support up to eight active control loops with minimum sample periods (for eight active loops) of 100ms (50ms for four active loops). This could involve processing up to four analogue, two RTD, four digital inputs, five relay outputs, four transistor outputs - and an optional four analogue outputs (4-20mA) - a total of 21 I/O - simultaneously.

The control/supervisory functions provided by the mxControl are virtually unlimited due to the unit's functionality and flexible software configuration. These are complemented by additional features such as display, transmission and recording of pressure, pH/ORP, conductivity, O2, CL2, level, temperature and TDS, frequency filter, password protection, alarm output, engineering units and an inverse function for on/off and proportional control.

Safeguarding the continuous operation of the mxControl against the elements is IP65 (NEMA 4X) ingress protection. A replaceable Lithium battery with a ten-year life backs up the mxControl's real-time clock.


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