Bürkert Control head type 8681 FM approval, article number 261484. Key data: Connection G 1/4 (internal thread), Voltage 12-28 V DC, Ambient temperature 5 °C to +55 °C, Protection class IP65/67. Order code: 8681-B-3-IX-E-0-SR-GV-0-00-E-0-0.
The Type 8681 control head is optimized for the decentralized automation of hygienic process valves. Thanks to its universal adaptation, it can be combined with all commercially available flaps, ball valves, single- and double-seat valves. In the decentralized automation concepts, the control head takes over the complete pneumatic control, feedback and diagnostic function up to bus communication. The housing is characterized by good cleanability, tried-and-tested IP protection and chemically resistant materials for use in hygienic process plants in the beverage, food and pharmaceutical industries. Depending on the process valve, up to 3 pneumatic drive chambers can be controlled independently of each other. The switching speeds for both directions of movement can be adjusted separately. A built-in check valve prevents the process valves from switching malfunctions due to back pressure. The process valve switching positions are detected via the inductive, analog displacement transducer and reported back to the higher-level control system. Up to 3 switching points can be set by the teach-in function at the touch of a button or automatically determined by predefined autotune functions. In addition, a 4th switching position can be read in and reported via an external inductive proximity switch. The illuminated coloured status indicator signals the respective switching position of the process valve or diagnostic functions such as maintenance requirements or fault conditions. The pilot valves are equipped with mechanical hand control. When the device is closed, the patented magnetically coded manual operation allows the main drive to be switched from the outside. Bus communication is possible with AS-Interface, IO-Link or büS/CANopen.
