BURKERT Fluid Control Systems has a tried and tested alternative to the conventional process control loop. Normally it is essential to have a process controller in a clean environment to provide the necessary proportional, integral and derivative functions necessary for accurate control.
Burkert's alternative combines the process controller, valve positioner, valve actuator and valve into one unit called ‘Top Control’.
The advantage of Top Control is that:
* The installation is easier and less time consuming.
* There is a major cost saving because of reduced cable runs and the elimination of additional equipment.
Top Control comes complete with a full PID control capability allowing for true decentralised automatic control. Signals (4-20mA, Frequency or Pt 100 RTD) from a suitable transmitter monitoring the process variable can be connected directly to the valve.
This assembly will provide full automatic control where the process variable is maintained against a pre-determined set point programmed into the unit.
There is an integral display showing the local set point, measured variable (in engineering units) and all valve set-up functions.
Set-up is done via a three-button keypad and easily understood menu. Stroke limiting, split range, and limit switches are provided.
Top Control also allows for supervisory functions such as remote set point, valve position feedback, etc., via conventional 4-20mA signals or Profibus.
Service and commissioning is simplified as the unit has the facility to automatically set the valve stroke from open to closed under actual plant conditions.
Compensation for the valve characteristic can be selected from standard curves or freely programmed into the controller.
Top Control can be combined with a number of different types of valve construction such as ball, butterfly, plug and diaphragm.