Apparatus for providing non-redundant secondary access to field devices in a distributed control system

• US 5,793,963 A
• Filed: 07/15/1997
• Issued: 08/11/1998
• Est. Priority Date: 10/24/1994
• Status: Expired due to Term

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Tapperson, Gary, Boyd, Thomas Andrew
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US08/893,126
• Time in Patent Office: 392 Days
• Field of Search: 395/200.31, 395/200.54, 395/200.47
• US Class Current: 709/201
• CPC Class Codes: G05B 19/4185 characterised by the network communication
• CPC Class Codes: G05B 2219/31122 Bridge between networks
• CPC Class Codes: G05B 2219/31162 Wireless lan
• CPC Class Codes: G05B 2219/31251 Redundant access, wireless and hardware access to fielddevices
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

An apparatus for accessing field devices in a distributed control system provides non-redundant secondary access to a plurality of field devices that are controlled by a control room. The field devices are coupled to a Fieldbus control network. In a first embodiment, each field device is provided with a wireless Fieldbus port that is accessible by a wireless handheld unit or wireless terminal. In a second embodiment, each Fieldbus control network is provided with a field module having a wireless Fieldbus port that allows all devices connected to the Fieldbus control network to be accessed by a wireless handheld unit or a wireless terminal. In a third embodiment, an H2-to-H1 Fieldbus bridge (which may service a plurality of H1 control networks) is provided with a wireless Fieldbus port that allows all Fieldbus devices connected to H1 control networks serviced by the H2-to-H1 bridge to be access by a wireless handheld unit of a wireless terminal. In a fourth embodiment, a bridge/converter provides an interface between older analog control room components and newer Fieldbus field devices. In one configuration, the bridge/converter includes a hard-wired Fieldbus port connected to a terminal, which may be in the control room. In another configuration, the bridge/converter includes a wireless Fieldbus port that allows a wireless handheld unit or a wireless terminal to access the Fieldbus devices serviced by the bridge/converter. The present invention allows a maintenance person to access Fieldbus field devices while servicing a device in the field, and allows secondary functions of field devices (which vary by manufacturer) to be accessed from a single remote unit.

Claims

1. A distributed control system for controlling material flow within an industrial process, comprising:

a plurality of industrial process control field devices for sensing or altering material flow within the industrial process, each industrial process control field device having first and second control functions;

first control means connected via a first respective signal path to each industrial process control field device to communicate first signals between the first control means and each industrial process control field device, for controlling the first control function and not the second control function; and

second control means connected via a second respective signal path to each industrial process control field device to communicate second signals between the second control means and each industrial process control device for controlling the second control function of each industrial process control field device, thereby providing non-redundant control of the second control function of each industrial process control field device.

2. The distributed control system of claim 1 wherein the second control means comprises:

a wireless signal processor connected to each industrial process control field device , for providing non-redundant control of the second control function via wireless second signals communicated through the wireless signal processor to each industrial process control field device.

3. The distributed control system of claim 2 wherein the first control means sup plies operating power via the first signal path to each industrial process control field device, and further including:

means for supplying operating power from the first signal path to the wireless signal processor.

4. The system of claim 3 wherein the wireless signal processor is part of a field module connected to the industrial process control field device, and the means for supplying operating power includes a connection of the wireless signal processor to the first signal path.

5. The system of claim 3 including a bridge in the first signal path, wherein the means for supplying operating power includes a connection of the wireless signal processor to the bridge.

6. The system of claim 3 wherein the means for supplying operating power includes a connection of the wireless signal processor to the industrial process control field device.

7. The distributed control system of claim 1 further comprising:

a first wireless transceiver coupled to each industrial process control field device; and

wherein the second control means includes a second wireless transceiver, for remotely controlling the second control function of each industrial process control field device via wireless second signals communicated between the first and second wireless transceivers.

8. The system of claim 7 wherein the second wireless transceiver is programmable to communicate with each industrial process control field device.

9. The system of claim 7 wherein the first and second transceivers communicate via at least one of radio, infrared, visible light, and ultrasonic communications.

10. The distributed control system of claim 1 wherein the second control means comprises:

a remote terminal connected via the second signal path to each industrial process control field device to communicate the second signals to each industrial process control field device to exclusively control the second control function of each field device via second signals substantially confined to the second signal path.

11. The system of claim 1 wherein the second control function of each industrial process control field device outputs status signals for the respective industrial process control field device, the status signals including at least one of diagnostic signals, identity signals, and calibration signals.

12. The system of claim 1 wherein each industrial process control field device includes a member of the group consisting of a valve positioner, a flow transmitter, a temperature sensor, and a pressure sensor.

13. A distributed control system for controlling material flow within an industrial process, comprising:

a plurality of industrial process control field devices for sensing or altering material flow within the industrial process, each industrial process control field device having first and second control functions, the first control function for altering or sensing material flow and the second control function for generating a status signal for the respective industrial process control field device,

central control means coupled via a respective signal path to each industrial process control field device, for controlling the first control function and not the second control function of each industrial process control field device via respective first signals substantially confined to the respective signal path;

a first wireless transceiver for requesting and receiving the status signal for each industrial process control field device; and

second wireless transceiver that connects to each industrial process control field device, for accessing the second control function of each industrial process control field device in response to requests from the first wireless transceiver and for sending the status signal of each industrial process control field device to the first wireless transceiver, thereby providing non-redundant access to the status signal of each industrial process control field device.

14. The distributed control system of claim 13 wherein the central control means supplies operating power via the respective signal path to each industrial process control field device, and further including:

means for supplying power from one respective signal path to the second wireless transceiver.

15. The system of claim 14:

wherein the second wireless transceiver is part of a field module that connects to each of the industrial process control field devices; and

wherein the means for supplying operating power includes a connection of the second wireless transceiver to the one respective signal path.

16. The system of claim 14 including a bridge in the one respective signal path, wherein the means for supplying operating power includes a connection of the second wireless transceiver to the bridge.

17. The system of claim 14 wherein the means for supplying operating power includes a connection of the second wireless transceiver to one of the industrial process control field devices.

18. The system of claim 13 wherein the status signal includes at least one diagnostic, identity, or calibration signal for the respective industrial process control field device.

19. The system of claim 13 wherein at least one of the industrial process control field devices includes a member of the group consisting of a valve positioner, a flow transmitter, a pressure sensor, and temperature sensor.

20. The system of claim 13 where in the first and second wireless transceivers communicate via at least one of radio, infrared, visible light, and ultrasonic communications.

21. The system of claim 13 wherein the first wireless transceiver is programmable to communicate with each industrial process control device.

22. In a distributed control system including a first industrial progress control field device having first status means for generating first status signals, and a second industrial process control field device having second status means for generating second status signals, a controller connected via respective signal paths to the first and second industrial process control field devices to send respective control signals to the first and second industrial process control field devices but not to receive the first and second status signals, the respective control signals being substantially confined to the respective signal paths, the improvement comprising:

a first wireless transceiver for receiving the first and second status signals;

a second wireless transceiver for connection to the first and second status means of the first and second industrial process control field devices, to send the first and second status signals to the first wireless transceiver, thereby providing non-redundant wireless access to the status signals of the first and second industrial process control field devices.

23. The system of claim 22 wherein the first and second status signals include at least one of diagnostic, identity, and calibration data.

24. The distributed control system of claim 22 wherein the controller supplies operating power via the respective signal path to each industrial process control field device, and further including:

means for supplying power from one respective signal path to the second wireless transceiver.

25. The system of claim 22:

wherein the second wireless transceiver is part of a field module that connects to each of the industrial process control field devices; and

wherein the means for supplying operating power includes a connection of the second wireless transceiver to the one respective signal path.

26. The system of claim 22 including a bridge in the one respective signal path, wherein the means for supplying operating power includes a connection of the second wireless transceiver to the bridge.

27. The system of claim 22 wherein the means for supplying operating power includes a connection of the second wireless transceiver to one of the industrial process control field devices.