Programmable logic control device with integrated database driver

Abstract

The invention relates, in particular, to an automation system (10; 110), in which a programmable logic control device (20; 120) can be connected via a network (100; 200) to a database system (60; 160). So that the programmable logic control device (20; 120) can exchange data directly with the database system (60; 160), the programmable logic control device (20; 120) has a first driver module (42; 132) associated with a physical interface (50; 150) for controlling data transmission via the network (10; 110) and also a second driver module (41; 132) for controlling the data exchange with the database device (60; 160).

Description

The invention is described in more detail below with reference to two embodiments in connection with the enclosed drawings. Shown are:

FIG. 1, an example data transmission system with a PLC and a database system, which can exchange data via a corresponding database driver, and

FIG. 2, an alternative embodiment of a data transmission system, in which a PLC can exchange data with a database device.

FIG. 1 shows schematically a section from an example automation system 10, in which a programmable logic control device 20, called PLC for short below, can exchange data directly with a database system 60 via a network. The network is shown schematically in the present example by a connection line 100, which can be, for example, an Ethernet connection. Conventionally, the programmable logic control device 20 has an application level 30, in which application software, for example for controlling, monitoring, and configuring the automation system 10, is stored. In the application level 30, a function block 31 is additionally shown which can start and terminate function calls for reading data from a database and/or for writing data into a database. It should be noted that the software in the application level 30 is preferably written in a language of the IEC 61131 standard. Furthermore, in a known way the PLC 20 contains an operating system and/or firmware level 40. So that the PLC 20 can transmit data to the database system 60 and can request data from this system, a proprietary database driver 41, which converts the function calls from the function block 31 into corresponding database control commands, is implemented in the operating system or the firmware level 40 of the PLC 20. With the help of the proprietary database driver 41, the PLC 20 is in the position to exchange data with the database system 60 via the network 100. In particular, the PLC 20 can request data from the database system 60 by means of the proprietary database driver 41. Furthermore, implemented in the operating system or firmware level 40 is a hardware driver that feeds the commands coming from the proprietary database driver 41 to a physical interface 50. The database control commands are then transmitted from the physical connection 100 via the network 100 to a corresponding physical interface 90 of the database system 60.

In a known way, the database system 60 contains an operating system that has a hardware driver 82 and a proprietary database driver 81, which can exchange data with the proprietary database driver 41 of the PLC 20. In addition, the database system 60 contains a data memory, that is, the actual database 70.

An alternative embodiment of a data transmission system 110 is shown in FIG. 2.

A network is shown schematically, in turn, by a connection 200, which connects a programmable logic control device 120, called PLC for short, and a database system 160 to each other.

An essential difference from the programmable logic control device 20 shown in FIG. 1 consists in that the PLC 120 contains a database driver 132 in the application level 130 of the PLC 120 instead of a proprietary database driver arranged in the firmware or in the operating system of PLC 20. Implemented in the database driver 132 is a communications protocol, for communications with the database system 160, that is written in a language of the IEC 61131 standard. Both the application software of the PLC 120 and also the function call module 131 are written in a language of the IEC 61131 standard. The function call module 131 comprises control software, with whose help application programs of the PLC 120 can be transmitted to the database system 160 and can be read from the database system 160 or a database 170 implemented in the database system. Because the database driver 132 has been written independent of the firmware or the operating system of the PLC 120, the PLC 120 can communicate with usual standard database drivers. Consequently, such a standard database driver 181 is implemented in the database system 160 in the operating system level 180.

If the database driver 132 is written in an IEC 61131 language, it is also possible to write a hardware driver 133 in an IEC 61131 language and to implement it in the application level 130 of the PLC 120. Alternatively, the hardware driver 133 can also be a component of the firmware or the operating system of the PLC 120. This variant is not shown.

Similarly to the system 10 shown in FIG. 1, both the PLC 120 and also the database system 160 have a physical interface 150 or 190, by means of which the data can be transmitted via the network 200. Similarly to the database system 60, the database system 160 also has a hardware driver 182 in the operating system level in addition to the standard database driver 181.

Furthermore, the PLC 120 has at least one input interface 152, to which a sensor (not shown) can be connected. Furthermore, at least one output interface 154 is provided, to which an actuator (also not shown) can be connected.

If the network is Ethernet, the hardware driver of the PLC and the database system contain the required TCP-IP protocol driver, which converts the data to be transmitted to the Ethernet format in a known way.

As an example, the function of the database transmission system 110 is explained below in connection with FIG. 2.

First, it shall be assumed that a temperature sensor, which regularly transmits temperature data to the PLC 120, is connected to the input interface 152 of the PLC 120. To be able to store the temperature data received at the PLC 120 in the database 170, a control program running in the PLC 120 accesses the function call module 131 in order to signal to the database driver 132 that data is now to be transmitted to the database system 160. The corresponding database write instruction is transmitted from the database driver 132 to the hardware driver 133, which converts the database write instruction into a data format that can be transmitted via the physical interface 150 and the Ethernet 200 to the physical interface 190 of the database system 160. From there, the database write instruction is forwarded via the hardware driver 182 to the standard database driver 181. Now it is signaled to the database system 160 that temperature data, which is to be stored in the database 170, is arriving from the PLC 120. The temperature data is transmitted from the PLC 120 either together with the database write instruction or writing at a later time to the database system 160 and written into the database 170. Under the control of a data management program, which is implemented in the standard database driver 181, the received temperature data is stored at corresponding locations in the database 170.

Thanks to the database driver 132, an application program running in the PLC 120 can also read data from the database 170. For this purpose, the application program accesses the function call module 131 in order to prompt the PLC 120 to transmit a database read instruction via the database driver 132, the hardware driver 133, and the physical interface 150 to the physical interface 190 of the database system 160, and from there via the hardware driver 182 to the standard database driver 181 of the database system 160. The database read instruction contains information on the data that the application software of the PLC 120 would like to request. Then the corresponding data is read out from the database 170 under the control of the standard database driver 181 and transmitted to the PLC 120.

Claims

1. Data transmission system (10; 110) with at least one memory-programmable control device (20; 120) and at least one database device (60; 160) that are connected to each other via a network (100; 200), wherein the memory-programmable control device (20; 120) has the following features: a first driver module (42; 133) associated with a physical interface (50; 150) for controlling data transmission via the network (100; 200) and a second driver module (41; 132) for controlling the data exchange with the database device (60; 160).

2. Data transmission system according to claim 1, characterized in that the second driver module (132) is implemented in the application level (130) of the memory-programmable control device (120).

3. Data transmission system according to claim 2, characterized in that the second driver module (132) contains a database communications protocol that is written in a language according to the IEC 61131 standard.

4. Data transmission system according to claim 3, characterized in that the first driver module (133) is implemented in the user level (130) or is part of the operating system or the firmware of the memory-programmable control device (120).

5. Data transmission system according to claim 4, characterized in that the first driver module (133) contains a communications protocol that is written in a language of the IEC 61131 standard.

6. Data transmission system according to claim 2, characterized in that the database device (160) contains a standard database driver (181) for communications with the second driver module (132) of the memory-programmable control device (120).

7. Data transmission system according to claim 1, characterized in that the second driver module (41) is part of the operating system or the firmware (40) of the memory-programmable control device (20).

8. Data transmission system memory system according to claim 1, characterized in that the second driver module (41; 132) can execute commands and functions of a conventional communications protocol for database systems.

9. Database transmission system according to claim 1, characterized in that the network (100; 200) is a TCP/IP based network.

10. Memory-programmable control device (20; 120) comprising: a first driver module (42; 133) associated with a physical interface (50; 150) for controlling data transmission via a network (100; 200); anda second driver module (41; 132) for controlling the data exchange with an external database device (60; 160).

11. Memory-programmable control device (20; 120) according to claim 10, characterized in that the second driver module (132) is implemented in the application level (130) of the memory-programmable control device (120).

12. Memory-programmable control device (20; 120) according to claim 11, characterized in that the second driver module (132) contains a database communications protocol that is written in a language according to the IEC 61131 standard.

13. Memory-programmable control device (20; 120) according to claim 12, characterized in that the first driver module (133) is implemented in the user level (130) or is part of the operating system or the firmware of the memory-programmable control device (120).

14. Memory-programmable control device (20; 120) according to claim 13, characterized in that the first driver module (133) contains a communications protocol that is written in a language of the IEC 61131 standard.

15. Memory-programmable control device (20; 120) according to claim 10, characterized in that the second driver module (41) is part of the operating system or the firmware (40) of the memory-programmable control device (20).