Data processing: generic control systems or specific application – Generic control system – apparatus or process
Reexamination Certificate
1997-08-13
2001-07-03
Grant, William (Department: 2121)
Data processing: generic control systems or specific application
Generic control system, apparatus or process
C700S096000
Reexamination Certificate
active
06256544
ABSTRACT:
The invention relates to a manufacturing installation which comprises a plurality of functional units carrying out at least one function and cooperating in the manufacturing installation, each of the functional units comprising at least one actor (e.g., actuator) and at least one sensor for function control and/or function monitoring.
To date, the so-called “central intelligence” concept has been used in such manufacturing installations. According to this concept, each functional unit has associated with it a unit which either detects signals of a sensor and passes them via a so-called field bus system to the central system controls or detects signals from the central computer and controls the actor in accordance with these.
This concept makes it necessary for a large amount of data to be exchanged via the field bus system, which, in itself, causes considerable susceptibility.
The object underlying the invention is, therefore, to so improve a manufacturing installation of the generic kind that it is less susceptible.
This object is accomplished in accordance with the invention in a manufacturing installation of the kind described at the outset in that the functional unit comprises at least one intelligent control unit which operates independently of a central computer and in accordance with a function control program of its own stored in a program memory, with the control unit controlling the at least one actor and evaluating signals of the at least one sensor in accordance with the function control program.
The advantage of the inventive solution is to be seen in the fact that each function step no longer has to be processed via the field bus in the central computer. Instead, the control unit makes it possible to process the function steps of the functional unit independently. The communication requirement and hence also the susceptibility involved therein are thereby considerably reduced.
With the inventive concept it does, in principle, remain possible, in the case of special functions, for example, involving considerable computing time, to revert to a central computer via a bus system. However, this has the disadvantage that the program structure acquires considerable complexity.
With a view to achieving a program structure which is as uninvolved as possible, it is, therefore, particularly advantageous for each control unit to independently carry out all the provided functions with the function control program, i.e., for it itself to carry out all computing operations required for the functions so that each control unit is self-sufficient in this respect.
The advantage of this solution is also to be seen in the fact that the susceptibility to failure is considerably reduced owing to the provided functions being able to be carried out independently of the functionability of the communication of the control unit with other units.
In the extreme case, the inventive concept could be realized in such a way that the function control program operates without information from the other control units of the other functional units. However, such isolated operation is not realizable in complex manufacturing installations.
It is, therefore, necessary to make provision for communication between the individual functional units. This is realized in accordance with the invention by the control unit of a functional unit communicating directly with the control unit of at least one other of the functional units. This means that by direct communication of the respective control unit with the control unit of at least one other of the functional units an exchange of information is possible. Therefore, in spite of the independent operating mode in each control unit, information from other functional units can be taken into account, and, consequently, it is possible to carry out the same complex control procedures with a decentral control system, as in the case of the “central intelligence” concept known from the prior art.
In the inventive solution, provision is, for example, made for each control unit to detect all function parameters necessary for the functions of the functional unit and to control the functional unit in accordance with these. This means that the control unit detects only function parameters as input values and hence is capable of independently deriving all control functions. This solution has the great advantage that each control unit requires only the function parameters as input values in order to be able to carry out the function control in its full scope.
For this reason, provision is made for the control unit to include at least part of the function parameters by evaluation of the signals of the at least one sensor. In the simplest case of an inventive manufacturing installation, it could also be sufficient to determine all function parameters by evaluation of the signals of the sensors associated with this control unit.
As stated above, in complex installations it is, however, necessary to obtain information and hence function parameters from other control units. Therefore, in this case, in accordance with the invention, the control unit detects part of the function parameters by communication with at least one of the other control units of the manufacturing installation.
In the case of communication provided between the individual control units it is particularly advantageous for all control units of the manufacturing installation to be connected to a bus system and to, therefore, be able to communicate with one another via the bus system.
Such a bus system can, for example, be a LON bus, an INTERBUS or a PROFIBUS.
For reasons of simplicity of the communication and flexibility of the structure of the inventive manufacturing installation, provision is preferably made for each control unit to be capable of receiving and transmitting communication signals via the bus system so that even when, in principle, no communication is necessary, it is possible to change this, if required, i.e., to set up communication with other control units.
In principle, it is sufficient to design the control units such that the function control program can be implemented in these, for example, by use of a corresponding program memory or by a corresponding programming connection.
If each control unit communicates via a bus system anyhow, it is particularly advantageous for each control unit to be programmable via the bus system as the bus system offers a particularly simple and advantageous possibility of reaching each control unit and hence programming each control unit via a programming station connected to the bus system, for example, by a function control program compiled by the programming station being loaded by the programming station via the bus system into the respective control unit.
Provision is also made in an advantageous variant of the inventive concept for the operating mode of each control unit to be checkable via the bus system so that it is possible to detect failures in both the hardware and the software via the bus system.
The easiest way of realizing this is for each control unit to deliver error messages via the bus system, for example, when a program error or hardware error occurs while the function control program is running.
In the above description of the inventive manufacturing installation it was not specified how the control unit is locally arranged.
It is, for example, possible to combine all control units—as is the case so far—in a switch cabinet which is locally arranged completely separate from the manufacturing installation.
It is, however, particularly advantageous for the control unit to be locally associated with each functional unit so as to eliminate the necessity for a large number of lines to lead from the switch cabinet to the individual functional units in order to connect their actors and sensors to the switch cabinet.
Even more advantageous is an embodiment wherein the at least one actor and the at least one sensor of each control unit are directly connected to the functional unit so it is possible to manufacture the functional unit together with th
Duerr Systems GmbH
Grant William
Lipsitz Barry R.
Rapp Chad
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