Flexible automation of a biotechnological pilot-plant with real-time network

The development of biochemical engineering towards integrated bioprocesses have influenced the demands of the applied control environment. In the pilot-plant of GBF we use a controller area network (CAN) based field-bus network to interconnect the decentralized process control computers under real-time conditions. In this paper the implementation and the performance of the CAN field-bus in an hierarchical automation concept is outlined. While some fermenters and downstream devices are connected to the network directly via an A/D converter and bus access in a so-called mini-module, other fermenters are automated with decentralized process computers which act as bus nodes with full functionality. A master computer interconnects several sub-nets and supervises the proper operating of all network components. In addition, a database is handled from this master, where all objects in the network, representing measured, controlled or online calculated variables, are specified. The CAN application layer enables an open communication from CAN-modules of different manufacturers. The CAN-message-specification allows the description of the data transfer between the individual user programs via a client/server model