Method and system of obtaining data from field devices

• US 8,144,028 B2
• Filed: 01/24/2005
• Issued: 03/27/2012
• 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: LaMothe, Brian P., Vanderah, Richard J., Willett, David S., Ellender, Damon J.
• Primary Examiner(s): Edwards, Jr., Timothy
• Application Number:
  US11/041,346
• Publication Number:
  US 20060168396A1
• Time in Patent Office: 2,619 Days
• Field of Search: 340/870.07, 702/56, 702/183, 714/25, 714/26, 714/46, 714/47
• US Class Current: 340/870.07
• 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;

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; 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 to the data cache across the first communication channel having a bandwidth of less than 256 megabits per second.

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

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 reading asset management data being one or both of field device status data and field device configuration data.

6. 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;

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;

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;

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.

7. A data caching device comprising:

a first communication port configured to implement a first communication protocol;

a second communication port coupled to the first communication port, the second communication port configured to implement a second communication protocol;

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

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

8. The data caching device as defined in claim 7 wherein the second communication protocol is different than the first communication protocol.

9. The data caching device as defined in claim 7 wherein the data throughput of the first communication port is greater than the combined data throughput of the second and third communication ports.

10. The data caching device as defined in claim 9 wherein the data caching device is configured to receive 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.

11. A system comprising:

a data acquisition system;

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

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;

a field device configured to create a datum;

a field controller, remotely located from the data acquisition system, coupled to the field device and the data cache, wherein the field controller is configured to obtain the datum from the field device, and the field controller is configured to send the datum to the data cache only if the datum is different than a previous datum sent to the data cache; 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.

12. The system as defined in claim 11 wherein the data acquisition system is a supervisory control and data acquisition (SCADA) system.

13. The system as defined in claim 11 wherein the field controller polls the field device for the datum.

14. The system as defined in claim 11 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.

15. The system as defined in claim 14 wherein the datum read by the field controller is a status of the transmitter, and wherein the field controller is configured to send 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.

16. The system as defined in claim 15 further comprising an asset management system coupled to the data cache, and wherein the asset management system is configured to obtain the status of the transmitter from the data cache.

17. The system as defined in claim 14 wherein the datum read by the field controller is a value of a field parameter, and wherein the field controller is configured to send 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.

18. The system as defined in claim 14 wherein the datum read by the field controller is configuration information of the transmitter, and wherein the field controller is configured to send the configuration information to the data cache only if the configuration information has changed from previous configuration information sent to the data cache.

19. The system as defined in claim 18 further comprising an asset management system coupled to the data cache, and wherein the asset management system is configured to obtain the configuration information of the transmitter from the data cache.

20. The system as defined in claim 14 wherein the transmitter is Highway Addressable Remote Transducer (HART) communication protocol compliant.

21. A system comprising:

a plurality of field devices configured to measure 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 is configured to obtain the measurement data using a request and response format requiring above a predetermined bandwidth;

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

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

said field controller is configured to obtain the measurement data from the plurality of field devices, and is configured to pass the measurement data to the data cache only if the measurement data has changed from previous measurement data;

said the data caching system is configured to cache the measurement data from the plurality of field devices and is configured to provide the measurement data to the SCADA system.

22. The system as defined in claim 21 wherein the field controller is configured to cache the measurement data.

23. The system as defined in claim 21 wherein the field controller is configured to obtain the measurement data by polling the plurality of field devices.

24. The system as defined in claim 21 further comprising:

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

said the data caching system is configured to obtain asset management data, and is configured to provide the asset management data to the asset management system.

25. The system as defined in claim 24 wherein the data caching system is configured to cache asset management data along with measurement data, and is configured to provide the asset management data to the asset management system.

26. The system as defined in claim 25 wherein the field controller is configured to read asset management data and is configured to send the asset management data to the data caching system only if the asset management data has changed from previous asset management data.

27. A system comprising:

a plurality of field devices configured to measure field parameters to create measurement data;

a data acquisition system, the data acquisition system is configured to obtain the measurement data using a request and response format;

a first caching system coupled to and proximate to the field devices, the first caching system configured to cache measurement data;

a second caching system coupled between the first caching system and the data acquisition system, the second caching system at a location remote from at least some of the field devices, and the second caching system is configured to cache measurement data provided by the first caching system only if the measurement data has changed from previous measurement data and further is configured to provide the measurement data to the data acquisition system upon request;

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 the bandwidth of the second communication channel is less than the predetermined bandwidth.

28. The system as defined in claim 27 wherein the second communication channel is configured to couple the first and second caching systems.

29. The system as defined in claim 27 wherein the first caching system is configured to obtain measurement data from the field devices using a request and response format.

30. 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 configured to communicate to field devices using a first communication protocol;

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

wherein the processor, executing a program, is configured to perform a process control loop and is configured to send commands to field control devices; and

wherein the processor, executing a program, is configured to receive data from the field devices over the first communication port, is configured to cache the data in the RAM, and is configured to send the data unsolicited to the data cache if the data has changed from previous data sent to the data cache.

31. The field controller as defined in claim 30 wherein the first communication port is configured to use a Highway Addressable Remote Transducer (HART) communication protocol.

32. The field controller as defined in claim 30 wherein the first communication port is configured to use a Foundation Fieldbus compliant communication protocol.

33. The field controller as defined in claim 30 wherein the processor, executing a program, is configured to receive status data for the field devices, and is configured to send the status data to the data cache over the second communication port if the status data has changed from previous status data.

34. The field controller as defined in claim 30 wherein the processor, executing a program, is configured to receive configuration data for the field devices, and is configured to send the configuration data to the data cache over the second communication port if the configuration data has changed from previous configuration data.