Field device for connecting controller to field bus system, has field device-base unit and interface-module for regulating bus-load current, controlling bus-signal transmission and supplying power supply for field device from field bus

摘要

The field device has a field device-base unit (1) and an interface-module (7) for regulating the bus-load current, controlling the bus-signal transmission and supplying power supply for the field device from a field bus. An auxiliary circuit is provided between a control transistor and the interface module for stabilizing the emitter-collector voltage of the control transistor independent from the bus voltage and for branching additional power supply for the field device gained from the difference-voltage between the bus voltage and the constant emitter-collector voltage.