Method for operating automation control equipment applications

• US 6,938,111 B2
• Filed: 04/19/2002
• Issued: 08/30/2005
• Est. Priority Date: 04/19/2002
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Herberth, Harald
• Primary Examiner(s): Auve, Glenn A.
• Assistant Examiner(s): Lee, Christopher E.
• Application Number:
  US10/125,917
• Publication Number:
  US 20030199998A1
• Time in Patent Office: 1,229 Days
• Field of Search: 710/1, 710/8, 710/48, 710/52, 710/260, 709/100, 709/318, 711/163, 700/3, 700/18, 700/19, 700/2, 364/134, 365/230.05
• US Class Current: 710/104
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/21097 DMA

Abstract

A method for operating automation control equipment applications ensures uninterrupted execution of a control application, at least during specific time periods, but such that the control application does not have the access privileges of a device driver. The operating system is configured for preventing calling of the processor commands from the control application, the processor communicating with the controlled automation equipment via a programmable bus interface. An embodiment of the method comprises the steps of performing read and write access of the control application to the bus interface directly and without routines of the operating system or device driver, and suspending processing of hardware interrupt calls of the processor during a preselected time period. Read and write access of the control application to the bus interface is thus carried out directly, rather than via routines of the operating system, and hardware interrupt calls of the processor are not processed during specific time periods.

Claims

1. A method for operating a control application for automation equipment having a control unit with at least one processor running under an operating system, the operating system configured for preventing calling of the processor commands from the control application, the processor communicating with the controlled automation equipment via a programmable bus interface, the method comprising the steps of:

performing read and write access by the control application to the bus interface directly; and

suspending processing of hardware interrupt calls of the process during a preselected time period;

wherein the control unit comprises a processor and bus interface adapted to read and write contents of a multi-port storage device, access of the bus interface to the storage device being prevented while the processor changes the contents of the storage device, and where hardware interrupt calls of the processor are not processed at least while access to the bus interface is prevented.

2. The method according to claim 1, wherein the prevention of the hardware interrupt calls of the processor comprises the steps of:

during the initialization of the control application, setting an input/output privilege level to a sufficiently high level to take precedence over hardware interrupt calls to the processor; and

during the program run, executing a command to clear an interrupt flag if the current input/output privilege level is at least as privileged as the set input/output privilege level.

3. The method according to claim 2 wherein the interrupt flag is cleared by the processor at the start of the changing of the contents of the storage device.

4. The method according to claim 3, wherein one command, selected from the group consisting of a command for setting an interrupt flag to the lowest privilege level and a command for popping data on top of a stack associated with the processor and storing the value in a flags register, is executed by the processor after the termination of the changing of the contents of the storage means.

5. The method according to claim 1, wherein the multi-port storage device comprises dual port random access memory.

6. The method according to claim 5, wherein the prevention of the hardware interrupt calls of the processor comprises the steps of:

during the initialization of the control application, setting an input/output privilege level to a sufficiently high level to take precedence over hardware interrupt calls to the processor; and

during the program run, executing a command to clear an interrupt flag if the current input/output privilege level is at least as privileged as the set level.

7. The method according to claim 6, wherein the interrupt flag is cleared by the processor at the start of the changing of the contents of the storage device.

8. A method for operating a control application for automation equipment having a control unit with at least one processor running under an operating system, the operating system configured for preventing calling of processor commands from the control application, the processor communicating with the controlled automation equipment via a programmable bus interface, the method comprising the steps of:

performing read and write access by the control application to the bus interface directly; and

suspending processing of hardware interrupt calls of the process during a preselected time period;

wherein the control unit comprises an Intel®

x86 compatible processor, and the prevention of the hardware interrupt calls of the processor comprises the steps of;

during initialization of the control application, setting of process parameter IOPL (IO Privilege Level) to the value 3; and

during a program run, executing command CLI.

9. The method according to claim 8, wherein the prevention of the hardware interrupt calls of the processor is cancelled by executing the command STI.

10. The method according to claim 9, wherein the prevention of the hardware interrupt calls of the processor is carried out in two steps:

during the initialization of the control application, setting a process parameter IPL (IO Privilege Level) to the value 3; and

during the program run, executing a POPF command.

11. The method according to claim 10, wherein the prevention of the hardware interrupt calls of the processor is cancelled by executing the command POPF.

12. The method according to claim 10, wherein one command selected from the group consisting of CLI and POPF is executed by the processor at the start of the changing of the contents of the storage means.

13. The method according to claim 10, wherein one command selected from the group consisting of the commands STI and POPF is executed by the processor after the termination of the changing of the contents of the storage means.

14. System for controlling an industrial process and associated automation equipment comprising:

a control unit with at least one processor running under an operating system, the operating system configured for preventing calling of the processor commands from a control application, the processor communicating with the controlled automation equipment via a programmable bus interface;

the processor programmed to perform read and write access by the control application to the bus interface directly; and

further programmed to suspend processing of hardware interrupt calls of the processor during a preselected time period;

wherein the control unit comprises a processor and bus interface adapted to read and write contents of a multi-port storage device, access of the bus interface to the storage device being prevented while the processor changes the contents of the storage device, and wherein hardware interrupt calls of the processor are not processed at least while access to the bus interface as prevented.

15. The system according to claim 14, wherein the processor is programmed to prevent hardware interrupt calls of the processor by setting, during the initialization of the control application, an input/output privilege level to a sufficiently high level to take precedence over hardware interrupt calls to the processor, and, during the program run, by executing a command to clear an interrupt flag if the current input/output privilege level is at least as privileged as the set input/output privilege level.

16. The system as claimed in claim 15, wherein processor is further programmed to clear the interrupt flag at the start of the changing of the contents of the storage device.

17. The system according to claim 16, wherein the processor is further programmed to execute a command, selected from the group consisting of a command for setting an interrupt flag to the lowest privilege level and a command for popping data on top of a stack associated with the processor and storing the value in a flags register, after the termination of the changing of the contents of the storage means.

18. The system according to claim 14, wherein the multi-port storage device comprises dual port random access memory.

19. The system according to claim 14, wherein the control unit comprises an Intel®

x86 compatible processor.

20. A system for storing data for access by a control application for controlling automation equipment having a control unit with at least one processor running under an operating system, the operating system configured for preventing calling of the processor commands from the control application, the processor communicating with the controlled automation equipment via a programmable bus interface, the control unit comprising a processor and bus interface, the memory comprising:

computer readable program code embodied therein for causing performance of read and write access by the control application to the bus interface directly; and

computer readable program code means embodied therein for causing suspension of processing of hardware interrupt calls of the process during a preselected time period; and

computer readable program code for causing reading and writing of contents of a multi-port storage device, for preventing access by the bus to the storage device while the processor changes the contents of the storage device, and for preventing hardware interrupt calls of the processor at least during accessing of the bus interface.

21. The memory according to claim 20, wherein the memory further comprises computer readable program code for preventing prevent hardware interrupt calls of the processor by setting, during the initialization of the control application, an input/output privilege level to a sufficiently high level to take precedence over hardware interrupt calls to the processor, and, during the program run, by executing a command to clear an interrupt flag if the current input/output privilege level is at least as privileged as the set input/output privilege level.

22. The memory according to claim 21, further comprising computer readable program code for causing clearing of the interrupt flag at the start of the changing of the contents of liter of the storage device.

23. The memory according to claim 22, further comprising computer program code for causing execution of a command, selected from the group consisting of a command for setting an interrupt flag to the lowest privilege level and a command for popping data on top of a stack associated with the processor and storing the value in a flags register, after the termination of the changing of the storage means.

24. The memory according to claim 20, wherein the multi-port storage device comprises dual port random access memory.

25. The memory according to claim 20, wherein the control unit comprises an Intel®

x86 compatible processor.