Distributed control system for controlling material flow having wireless transceiver connected to industrial process control field device to provide redundant wireless access

• US 6,236,334 B1
• Filed: 05/28/1997
• Issued: 05/22/2001
• 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): Luu, Le Hien
• Application Number:
  US08/864,750
• Time in Patent Office: 1,455 Days
• Field of Search: 1/1, 455/422, 707/201, 370/442, 370/310, 375/206, 340/825.37, 340/825.23
• US Class Current: 700/21
• 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 provides redundant wireless to access field devices in a distributed control system having primary access to the field devices provided by hard-wired media that couples the field devices to the 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 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 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 accessed by a wireless handheld unit of a wireless terminal. The redundant wireless access provided by the present invention allows a control room operator to access field devices in the event of failure or unavailability of the hard-wired media that provides primary access to the field devices.

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;

central control means connected via a primary hardwired communication link to the industrial process control field devices to communicate first signals between the central control means and the industrial process control field devices;

a first transceiver;

a second transceiver connected to at least one of the industrial process control field devices, the first and second transceivers providing redundant two-way wireless communications of second signals between the first transceiver and the second transceiver.

2. The system of claim 1 wherein the signal path comprises a twisted pair communication link electrically connecting the central control means to each industrial process control field device.

3.The system of claim 1 wherein at least one industrial process control field device of the plurality of field devices includes a member of the group consisting of a valve positioner, a flow transmitter, a pressure sensor, and a temperature sensor.

3. The system of claim 1 wherein the first and second transceivers communicate via at least one of radio, infrared, visible light, or ultrasonic communications.

4. The system of claim 1 wherein the second transceiver is part of a field module.

5. The system of claim 1 including a bridge in the signal path.

6. The system of claim 1 wherein the first and second transceivers provide wireless communications of second signals in the event of an interruption of the primary hardwired communication link.

7. The system of claim 1 wherein the first and second transceivers provide wireless communications of second signals in the event of shut down of at least a portion of the industrial process whose material flow is being sensed or altered by the at least one of the industrial process control field devices.

8. In a distributed control system including at least a first industrial process control field device for sensing material flow in an industrial process and at least a second industrial process control field device for altering material flow in the industrial process, central control means connected via a primary hardwired communication link to at least the first and second industrial process control field devices to receive sense signals from the first industrial process control field device, and to communicate control signals to the second industrial process control field device, thereby enabling the sensing and altering of material flow in the industrial process via the primary hardwired communication link, the improvement comprising:

a first wireless transceiver;

a second wireless transceiver for connection to the first and second industrial process control field devices, to provide redundant two-way wireless communications between the first wireless transceiver and the first and second industrial process control field devices via the second wireless transceiver, thereby enabling the sensing and altering of material flow in the industrial process via the first and second wireless transceivers.

9. The system of claim 9 wherein the signal path comprises twisted pair wiring.

10. The system of claim 9 wherein the second transceiver is part of a field module.

11. The system of claim 9 including a bridge in the signal path.

12. The system of claim 9 wherein the first and second transceivers provide wireless communications of second signals in the event of an interruption of the primary hardwired communication link.

13. The system of claim 9 wherein the first and second transceivers provide wireless communications of second signals in the event of shut down of at least a portion of the industrial process whose material flow is being sensed by the first industrial process control field device and whose material flow is being altered by the second industrial process control field device.