Now available, Burkert Fluid Control Systems ' new series of digital positioners is designed for expanded process control possibilities, without the draw-backs of traditional methods, such as zero air bleed at rest position.
Type 8791 Basic Positioner, 8792 Positioner and Type 8793 Positioner with integral Process Controller are for use with quarter turn and linear process valves, as well as virtually any pneumatically controlled instrument, such as non-Burkert valves, cylinders and dampers.
These digital positioners are available as direct mount or remote versions, all with IP65/67 housings for robust operation even in the most challenging of environments.
The large, backlit LCD display guides direct four button programming, giving the option of computer or direct inputs as well as direct parameter readout. These devices also come with built-in multi-tier security settings to stop ‘busy fingers'.
These digital positioners have an integrated pilot valve system which uses filtered and recycled air, thus avoiding contamination by poor quality air, which can often be a frequent cause of positioner failure.
Designed for low air use and no air use at the rest position, the pilot system is able to control up to 150 litres per minute for both spring return and double acting actuators; a significant improvement on traditional positioners.
For each type, a single unit is used for double acting and spring return type actuators with the same control functionality across all devices. The true IP65/67 ingress protection is reached with double seals, tough aluminium housing and high quality materials used throughout.
With digital technology, automatic positioner tune and process tune features have been included with one-minute push button commissioning even for full PID units. Furthermore, the digital technology delivers unlimited feedbacks and features not possible with old-style positioners, particularly when fieldbus network interfaces are utilised.
There are three versions available within this series of digital positioners; the standard positioner, the basic positioner and the positioner plus process controller.
The Type 8792 positioner is the standard model and the Type 8791 is the basic model, which delivers most standard features with LED indication rather than LCD display. This digital positioner is programmed via computer (or simple DIP switches). A panel mount version of the Basic is also available.
At the other end of the scale, the Type 8793 digital positioner with integral process controller has full PID on board, and is designed for discrete control loops or true DCS with network interface. With pt100, frequency and 4..20mA inputs as well as 4..20mA and 2 x binary output, each Type 8793 digital positioner can replace multiple expensive components from a traditional control loop.
“Smart features like same function across product lines help our partners in industry to decrease training and operational issues with a single system of technologies designed to work together," says Managing Director, Chris Hoey of the similarity of function of Burkert Fluid Control Systems' new digital positioners and the ELEMENT range of control valves launched last year.
“Adding to our process control package of German manufactured valves, pneumatics, instruments and controllers, the new digital positioners show why Burkert is the ideal partner in fluid control systems,” he says.