Control device and method for switching input/output units of a controller

#The invention relates to a controller comprising a control unit, which communicates with at least one input and /or output unit via a data bus for exchange of process data.

#The invention further relates to a method for switching of input and/or output units of a controller into a power state, in which the power consumption of the bus members, which are connectable to the input/output units, is reduced.

#For controllers, in particular for programmable logic controllers, it is often necessary to reduce the power consumption of bus members, which are connected to a peripheral field bus controlled control unit.

#The invention is explained in more detail subsequently by means of an exemplary embodiment and the enclosed figures. It shows:

#FIG. 1 a block diagram of a controller comprising a control unit, a field bus controller/-coupler and input/output units connected thereto;

#FIG. 2 a flow chart of a method for switching input/output units into a power-saving state.

#FIG. 1 shows a block diagram of a controller 1 that comprises a programmable logic controller unit (2) in per se known manner. The programmable logic controller 2 is adapted to execute a control program and to exchange process data P via a field bus 3 with at least one network node 4. The network node 4 comprises a field bus controller/-coupler 5. The field bus controller/-coupler 5 is adapted to convert data between the protocol of the field bus 3 to the communication protocol of an internal proprietary data transmission channel 6 and vice versa. Hereby the field bus controller/-coupler 5 comprises a processing unit 7 as well as a memory unit 8, which is connected thereto. In the memory unit 8 a process data image 9 is stored, in which process data P for the input/output units 10, which are connected to the field bus controller/-coupler 5 via the internal data transmission channel 6, are stored.

#Thereby an exchange of process data P takes place, from the process image 9 to the connected input/output units 10 and vice versa, via the data transmission channel 6. In this manner predetermined process data P can be written into the process data image 9 by means of the control unit 2 via the field bus 3. The field bus controller/-coupler 5 transmits these process data P from the process data image 9 to the input/output units 10, e.g. cyclic according to the communication protocol of the data transmission channel 6. These input/output units 10 can itself write process data P into the process data image 9 via the data transmission channel 6. These process data P can then be transferred from the field bus controller/-coupler 5 to the control unit 2 via the field bus 3.

#The input/output units 10 comprise one or a plurality of channels 11a, 11b, . . . , 11n respectively, to which the bus members 12 can be connected. Such bus members 12 can be actuators, sensors or other devices.