System and method for implementing safety instrumented systems in a fieldbus architecture

1. An apparatus for operating in a block-oriented safety related open control system comprising:

a memory, which includes at least one safety related component;

a processor, operably connected to the memory, wherein the processor executes the safety related component based on a system schedule;

a medium attachment unit, which translates input messages and output messages between the processor and a transmission medium using an extended safety-related protocol; and

wherein the processor manages the system schedule, instructs a second apparatus when it can execute a second safety related component, and passes a token to the second apparatus when a time arises for executing the second safety related component.

2. The apparatus of claim 1 , wherein the apparatus is operably connected to a high speed Ethernet bus.

3. The apparatus of claim 1 , wherein the memory includes at least one non-safety related component.

4. A process for communicating safety related data obtained by a first device to a second device comprising:

obtaining, using a first device, information useful ingenerating a first data sequence;

generating the first data sequence using the obtained information;

generating a first authenticator for the first data sequence;

combining the first data sequence and the first authenticator; and

communicating the combination to the second device.

5. The process of claim 4 , wherein the first device is a publisher and the second device is a subscriber in a publisher-subscriber communications architecture.

6. The process of claim 4 , wherein the first device is a client and the second device is a server in a client-server communications architecture.

7. A process for authenticating a received message, wherein the received message includes information pertaining to a safety related component, comprising:

receiving a first data sequence;

receiving a first authenticator related to the first data sequence;

generating a second data sequence based upon the first data sequence;

calculating a second authenticator based upon the second data sequence;

comparing the first authenticator and the second authenticator;

when the first authenticator and the second authenticator are not the same, rejecting the received message; and

when the first authenticator and the second authenticator are the same,

receiving a sequence number related to the first data sequence;

obtaining an expected sequence number; and

comparing the received sequence number to the expected sequence number;

when the received sequence number and the expected sequence number are not the same, rejecting the message; and

when the received sequence number and the expected sequence number are the same, accepting the message.

8. The process of claim 7 , wherein the process is used to authenticate a message communicated to a safety related component in a block-oriented safety related open control system.

9. The process of claim 7 , wherein the process is executed by a client in a client-server architecture.

10. The process of claim 9 , wherein the process comprises communicating a request to read a parameter related to a safety related component to a server and the first data sequence contains a response, communicated by the server, to the request.

11. The process of claim 7 , wherein the process is executed by a subscriber in a publisher-subscriber architecture.

12. The process of claim 7 , wherein the first data sequence includes data relating to a safety related component used by a device in an open control system.

13. The process of claim 12 , wherein the open control system utilizes a fieidbus architecture.

14. The process of claim 12 , wherein the first data sequence further includes at least one of a sequence number, an object index and a connection key.

15. The process of claim 12 , wherein the first data sequence further includes at least one of a sequence number, an object index and a connection key.

16. The process of claim 7 , wherein the first data sequence includes the first authenticator.

17. The process of claim 7 , wherein the first data sequence includes the sequence number.

18. The process of claim 7 , wherein the first data sequence includes at least one of an object index and a connection key.

19. The process of claim 7 , wherein the second data sequence comprises an expected connection key, a received sequence number, and an expected object index, wherein the received sequence number is received in the first data sequence.

20. The process of claim 14 , wherein the first data sequence comprises a sub-index.