Method and system of obtaining data from field devices

• US 20060168396A1
• Filed: 01/24/2005
• Published: 07/27/2006
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Emerson Automation Solutions Measurement Systems & Services LLC (Emerson Electric Company)
• Original Assignee: Daniel Measurement and Control Incorporated (Emerson Electric Company)
• Inventors: Vanderah, Richard J., LaMothe, Brian P., Ellender, Damon J., Willett, David S.
• Granted Patent: US 8,144,028 B2
• Time in Patent Office: Days
• US Class Current: 711/113
• CPC Class Codes: G05B 2219/24215 Scada supervisory control and data acquisition
• CPC Class Codes: G05B 2219/25206 Protocol: only devices with changed states communicate their states, event
• CPC Class Codes: G05B 2219/31121 Fielddevice, field controller, interface connected to fieldbus
• CPC Class Codes: G05B 23/0221 Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 2212/1016 Performance improvement

Abstract

Systems and methods for communicating data from field devices to data acquisition systems. In at least some exemplary embodiments, a remote process or field controller may obtain data, and send the data to a data cache only if the data has changed from previously sent data. The data acquisition system may poll the data cache for data. Having the remote process controller send only data that has changed allows the communication channel between the data caching system and the remote process controller to have a bandwidth or throughput lower than what may be needed to support the polling of the data acquisition system.

Claims

1. A method comprising:

obtaining data regarding a field parameter from a field device by a field controller;

sending the data from the field controller to a data cache only if the data is different by a predetermined amount than previous data sent to the data cache; and

operating a data acquisition system, wherein the data acquisition system polls the data cache at a polling frequency to obtain the data from the data cache.

2. The method as defined in claim 1 further comprising sending the data from the field controller to the data cache by way of a first communication channel, and wherein the bandwidth of the first communication channel is less than a bandwidth needed for the data acquisition system to poll at the polling frequency.

3. The method as defined in claim 2 further comprising sending the data to the data cache across the first communication channel having a bandwidth of less than 256 megabits per second.

4. The method as defined in claim 1 further comprising:

reading asset management data of the field device by the field controller; and

sending the asset management data to the data cache only if the data has changed from previous asset management data sent to the data cache.

5. The method as defined in claim 4 further comprising sending the data regarding the field parameter and the asset management data to the data cache by way of a first communication channel, wherein the bandwidth of the first communication channel is less than a bandwidth needed for the data acquisition system to poll at the polling frequency.

6. The method as defined in claim 4 further comprising reading asset management data being one or both of field device status data and field device configuration data.

7. The method as defined in claim 1 wherein obtaining further comprises polling the field device by the field controller.

8. A data caching device comprising:

a first communication port implementing a first communication protocol;

a second communication port coupled to the first communication port, the second communication port implementing a second communication protocol;

a third communication port coupled to the first communication port, the third communication port implementing a third communication protocol, and wherein the third communication protocol is different than the first communication protocol;

wherein the data caching device receives unsolicited data across the second and third communication ports and caches the data, and wherein the data caching device receives requests for the data across the first communication port and provides cached data to the first communication port upon substantially each request received.

9. The data caching device as defined in claim 8 wherein the second communication protocol is different than the first communication protocol.

10. The data caching device as defined in claim 8 wherein the data throughput of the first communication port is greater than the combined data throughput of the second and third communication ports.

11. The data caching device as defined in claim 10 wherein the data caching device receives requests at a request rate that requires a first data throughput, and wherein the combined data throughput of the second and third communication ports is less than the first data throughput.

12. A system comprising:

a data acquisition system;

a data cache coupled to the data acquisition system, wherein the data acquisition system polls the data cache for data regarding a plurality of field parameters;

a field device that creates a datum;

a field controller coupled to the field device and the data cache, wherein the field controller obtains the datum from the field device, and the field controller sends the datum to the data cache only if the datum is different than a previous datum sent to the data cache.

13. The system as defined in claim 12 further comprising:

a first communication pathway coupling the data acquisition system and the data cache, the first communication pathway having a bandwidth sufficient to carry the data acquisition system polls for data regarding the plurality of field parameters; and

a second communication pathway coupling the field device and the data cache, the second communication having a bandwidth insufficient to carry the data acquisition system polls for data regarding the plurality of field parameters.

14. The system as defined in claim 12 wherein the data acquisition system is a supervisory control and data acquisition (SCADA) system.

15. The system as defined in claim 12 wherein the field device is one selected from the group:

a pressure transmitter;

a flow transmitter;

a level transmitter, position transmitter, or a temperature transmitter.

16. The system as defined in claim 15 wherein the datum read by the field controller is a status of the transmitter, and wherein the field controller sends the status of the transmitter to the data cache only if the status of the transmitter changed from a previous status of the transmitter sent to the data cache.

17. The system as defined in claim 16 further comprising an asset management system coupled to the data cache, and wherein the asset management system obtains the status of the transmitter from the data cache.

18. The system as defined in claim 15 wherein the datum read by the field controller is a value of a field parameter, and wherein the field controller sends the value of the field parameter to the data cache only if the value of the field parameter has changed by a predetermined amount from a previous value of the field parameter send to the data cache.

19. The system as defined in claim 15 wherein the datum read by the field controller is configuration information of the transmitter, and wherein the field controller sends the configuration information to the data cache only if the configuration information has changed from previous configuration information sent to the data cache.

20. The system as defined in claim 19 further comprising an asset management system coupled to the data cache, and wherein the asset management system obtains the configuration information of the transmitter from the data cache.

21. The system as defined in claim 15 wherein the transmitter is Highway Addressable Remote Transducer (HART) communication protocol compliant.

22. The system as defined in claim 12 wherein the field controller polls the field device for the datum.

23. A system comprising:

a plurality of field devices measuring field parameters to create measurement data;

a supervisory control and data acquisition (SCADA) system coupled to the plurality of field devices, wherein the SCADA system obtains the measurement data using a request and response format requiring above a predetermined bandwidth; and

a communication network coupling the plurality of field devices to the SCADA system, wherein a portion of the communication network has a bandwidth less than the predetermined bandwidth.

24. The system as defined in claim 23 further comprising:

a data caching system coupled to the SCADA system by way of a first communication channel having a bandwidth at least as great as the predetermined bandwidth, and the data caching system coupled to the field devices by way of second communication channel having a bandwidth less than the predetermined bandwidth;

wherein the data caching system caches measurement data from the plurality of field devices and provides the measurement data to the SCADA system.

25. The system as defined in claim 24 further comprising:

a field controller coupled to the data caching system by way of the first communication channel, and also coupled to the plurality of field devices;

wherein the field controller obtains measurement data from the plurality of field devices, and passes the measurement data to the data cache only if the measurement data has changed from previous measurement data.

26. The system as defined in claim 25 wherein the field controller caches the measurement data.

27. The system as defined in claim 25 wherein the field controller obtains the measurement data by polling the plurality of field devices.

28. The system as defined in claim 24 further comprising:

an asset management system coupled to the data caching system by way of the first communication channel; and

wherein the data caching system obtains asset management data, and provides the asset management data to the asset management system.

29. The system as defined in claim 28 wherein the data caching system caches asset management data along with measurement data, and provides the asset management data to the asset management system.

30. The system as defined in claim 29 wherein the field controller reads asset management data and sends the asset management data to the data caching system only if the asset management data has changed from previous asset management data.

31. A system comprising:

a plurality of field devices measuring field parameters to create measurement data;

a data acquisition system, wherein the data acquisition system obtains the measurement data using a request and response format;

a first caching system coupled to the field devices, the first caching system caches measurement data; and

a second caching system coupled between the first caching system and the data acquisition system, wherein the second caching system caches measurement data provided by the first caching system and further provides the measurement data to the data acquisition system upon request.

32. The system as defined in claim 31 further comprising:

a first communication channel coupling the data acquisition system and the second data caching system, and wherein the bandwidth of the first communication channel is at least a great as a predetermined bandwidth for obtaining measurement data by the data acquisition system using the request and response format; and

a second communication channel coupling the second caching system to the field devices, and wherein the bandwidth of the second communication channel is less than the predetermined bandwidth.

33. The system as defined in claim 32 wherein the second communication channel couples the first and second caching systems.

34. The system as defined in claim 31 wherein the first caching system obtains measurement data from the field devices using a request and response format.

35. The system as defined in claim 31 wherein the first caching system sends the measurement data to the second caching system only if the measurement data has changed from previous measurement data.

36. A field controller comprising:

a processor;

a random access memory (RAM) coupled to the processor;

a first communication port coupled to the processor, the first communication port communicates to field devices using a first communication protocol;

a second communication port coupled to the processor, the second communication port communicates to a data cache system using a second communication protocol;

wherein the processor, executing a program, performs a processor control loop and sends commands to field control devices; and

wherein the processor, executing a program, receives data from the field devices over the first communication port, caches the data in the RAM, and sends the data to the data cache if the data has changed from previous data sent to the data cache.

37. The field controller as defined in claim 36 wherein the first communication port uses a Highway Addressable Remote Transducer (HART) communication protocol.

38. The field controller as defined in claim 36 wherein the first communication port uses a Foundation Fieldbus compliant communication protocol.

39. The field controller as defined in claim 36 wherein the processor, executing a program, receives status data for the field devices, and sends the status data to the data cache over the second communication port if the status data has changed from previous status data.

40. The field controller as defined in claim 36 wherein the processor, executing a program, receives configuration data for the field devices, and sends the configuration data to the data cache over the second communication port if the configuration data has changed from previous configuration data.