BECKHOFF BK3xx0 - Manual (Page 12)

Notes on the Documentation
10 Fieldbus Components
The Beckhoff Bus Terminal System
Up to 64 Bus Terminals each having 2 I/O channels for each signal form
The Bus Terminal system is the universal interface between a fieldbus system and the sensor / actuator level. A unit
consists of a Bus Coupler as the head station, and up to 64 electronic series terminals, the last one being an end
terminal. For each technical signal form, terminals are available each having two I/O channels, and these can be
mixed in any order. All the terminal types have the same mechanical construction, so that difficulties of planning and
design are minimized. The height and depth match the dimensions of compact terminal boxes.
Decentralized wiring of each I/O level
Fieldbus technology allows more compact forms of controller to be used. The I/O level does not have to be brought to
the controller. The sensors and actuators can be wired decentrally, using minimum cable lengths. The controller can
be installed at any location within the plant.
Industrial PCs as controllers
The use of an Industrial PC as the controller means that the operating and observing element can be implemented in
the controller’s hardware. The controller can therefore be located at an operating panel, in a control room, or at some
similar place. The Bus Terminals form the decentralized input/output level of the controller in the control cabinet and
the subsidiary terminal boxes. The power sector of the plant is also controlled over the bus system in addition to the
sensor/actuator level. The Bus Terminal replaces the conventional series terminal as the wiring level in the control
cabinet. The control cabinet can have smaller dimensions.
Bus Couplers for all usual bus systems
The Beckhoff Bus Terminal system unites the advantages of a bus system with the possibilities of the compact series
terminal. Bus Terminals can be driven within all the usual bus systems, thus reducing the controller parts count. The
Bus Terminals then behave like conventional connections for that bus system. All the performance features of the
particular bus system are supported.
Assembly on standardized C mounting rails
The easy, space-saving, assembly on a standardized C-rail, and the direct wiring of actuators and sensors, without
cross-connections between the terminals, standardizes the installation. The consistent labelling scheme also
contributes.
The small physical size and the great flexibility of the Bus Terminal system allows it to be used wherever a series
terminal is also used. Every type of connection, such as analog, digital, serial or the direct connection of sensors can
be implemented.
Modularity
The modular assembly of the terminal strip with Bus Terminals of various functions limits the number of unused
channels to a maximum of one per function. The presence of two channels in one terminal is the optimum
compromise of unused channels and the cost of each channel. The possibility of electrical isolation through potential
feed terminals also helps to keep the number of unused channels low.
Display of the channel state
The integrated LEDs show the state of the channel at a location close to the sensors and actuators.