Interface for use with a process instrumentation system

• US 5,432,711 A
• Filed: 10/16/1992
• Issued: 07/11/1995
• Est. Priority Date: 10/16/1992
• Status: Expired due to Fees

• Current Assignee: Elcon Instruments Incorporated
• Original Assignee: Elcon Instruments Incorporated
• Inventors: Jackson, Steve T., Gattanini, Carlo L., Novelli, Giorgio
• Primary Examiner(s): Ramirez, Ellis B.
• Assistant Examiner(s): PEESO, THOMAS R
• Application Number:
  US07/962,107
• Time in Patent Office: 998 Days
• Field of Search: 364/579, 364/514, 364/509, 364/514, 364/131, 364/709.1, 364/550, 364/551.01, 361/111, 371/15.1
• US Class Current: 700/2
• CPC Class Codes: G06F 11/273 Tester hardware, i.e. output processing circuits G06F11/263 takes precedence

Abstract

The present invention relates to an interface for a maintenance system used in conjunction with a process instrumentation system. More specifically, the invention relates to an interface used for maintaining and configuring smart devices. Even more specifically, the invention relates to an interface that may safely be used to maintain and configure smart devices where such smart devices are located in hazardous areas. The interface, which may be removably mounted to a termination board, has a control section, a port replacement section, a permanent storage section, a temporary storage section, an address/data bus, a UART, a standard clock pulse generation device, an option select device, a modem, a channel selection decoder, a wave shaping device, and at least one multiplexer. The interface and a termination board for use in process instrumentation systems that require intrinsic safety are explained by themselves and in system and function contexts.

Claims

1. Apparatus mountable onto a termination board for use with a plurality of removably mountable intrinsically safe electronic barriers each of which couples a different microprocessor-equipped smart device in a first area to a process controller in a second area, each smart device generating process control information onto a control loop indicative of a condition in said first area and including means for receiving a maintenance command over said control loop for performing a maintenance operation, said apparatus comprising:

selecting means for selecting one of a plurality of outputs each connectable to one of said plurality of intrinsically safe electronic barriers, such that each output when selected electrically connects to one of said control loops used for transmitting process control information between a corresponding smart device and said process controller;

generating means for generating a frequency shift key modulated signal modulated in accordance with a maintenance command to be transmitted to one of said smart devices; and

a microprocessor, coupled to said selecting means and said generating means, for controlling said selecting means to select one of said plurality of outputs and providing said frequency shift key modulated signal to a control loop corresponding to said selected one output, wherein said frequency shift key modulated signal modifies a process control signal on said control loop corresponding to said selected one output without interfering with process control information transmitted over said control loop corresponding to said selected one output; and

means for removably mounting said means for selecting, said means for generating, and said microprocessor onto said termination board in a manner substantially similar to the manner in which said plurality of removably mountable intrinsically safe electronic barriers are removably mounted onto said termination board.

2. The apparatus of claim 1, further comprising a second apparatus adapted to be removably mounted onto a second termination board for use with a second plurality of removably mountable intrinsically safe electronic barriers each of which couples a different smart device located in said first area to said process controller, said second apparatus for generating a second frequency shift keyed signal for one of said second plurality of removably mountable intrinsically safe electronic barriers, wherein said first and second apparatus each comprises an RS-485 interface for receiving maintenance commands from a maintenance processor over an RS-485 link.

3. The apparatus of claim 1, wherein said means for removably mounting comprises a single rectangular housing having a connector on one face, said single rectangular housing disposed to mount said apparatus in parallel with said plurality of intrinsically safe electronic barriers on said termination board.

4. The apparatus of claim 1, further comprising an option select device, coupled to said microprocessor, for selecting a unit address and a baud rate for communicating with a maintenance processor.

5. Apparatus mountable onto a termination board having means for receiving a plurality of removably mountable intrinsically safe electronic barriers each of which couples a different microprocessor-equipped smart device located in a hazardous area to a process controller located in a safe area, each smart device generating process control information onto a control loop indicative of a condition in said hazardous area and including means for receiving a maintenance command over said control loop for performing a maintenance operation, said apparatus comprising:

an assembly adapted to be removably mounted onto said termination board comprising a multiplexer having a plurality of outputs each connectable to one of said plurality of intrinsically safe electronic barriers, such that each output when selected electrically connects within one of said intrinsically safe electronic barriers to one of said control loops used for transmitting process control information between a corresponding smart device and said process controller;

an FSK modem, coupled to said multiplexer, for generating a frequency shift key modulated signal modulated in accordance with a maintenance command to be transmitted to one of said smart devices;

a microprocessor, coupled to said multiplexer, for controlling said multiplexer to select one of said plurality of outputs and providing said frequency shift key modulated signal to a control loop corresponding to said selected one output, wherein said frequency shift key modulated signal modifies a process control signal on said control loop corresponding to said selected one output without interfering with process control information transmitted over said control loop corresponding to said selected one output; and

means for removably mounting said assembly to said termination board in a manner substantially similar to the manner in which said plurality of removably mountable intrinsically safe electronic barriers are mounted onto said termination board.

6. The apparatus of claim 5, wherein said removable mounting means comprises a rectangular housing having a connector on one face, said rectangular housing and connector disposed to mount said assembly in parallel with said plurality of removably mountable intrinsically safe electronic barriers on said termination board.

7. The apparatus of claim 5, wherein each of said multiplexer outputs is coupled to and electrically connects to one of said plurality of intrinsically safe electronic barriers on the safe side of the barrier.

8. The apparatus of claim 5, further comprising means, disposed on said termination board, for connecting said microprocessor to a second microprocessor located on a second termination board, said connection being in parallel with a maintenance workstation which generates said maintenance command.

9. The apparatus of claim 5, further comprising a cross-wiring section, mounted to said termination board, for cross-wiring one of said intrinsically safe electronic barriers to a particular smart device.

10. The apparatus of claim 5, wherein said microprocessor receives said maintenance command from a maintenance processor through the use of an RS-485 protocol.

11. The apparatus of claim 5, further comprising a second apparatus adapted to be removably mounted onto a second termination board having means for receiving a second plurality of removably mountable intrinsically safe electronic barriers each of which couples a different second smart device located in said hazardous area to said process controller located in said safe area, each second smart device generating process control information onto a second control loop indicative of a condition in said hazardous area and including means for receiving a maintenance command over said second control loop for performing a maintenance operation, said second apparatus comprising:

a second assembly adapted to be removably mounted onto said second termination board, comprising

a second multiplexer having a plurality of second outputs each connectable to one of said second plurality of intrinsically safe electronic barriers, such that each second output when selected electrically connects within one of said second intrinsically safe electronic barriers to one of said second control loops used for transmitting process control information between a corresponding second smart device and said process controller;

a second FSK modem, coupled to said second multiplexer, for generating a second frequency shift key modulated signal modulated in accordance with a second maintenance command to be transmitted to one of said second smart devices; and

a second microprocessor, coupled to said second multiplexer, for controlling said second multiplexer to select one of said plurality of second outputs and providing said second frequency shift key modulated signal to a control loop corresponding to said selected one second output, wherein said second frequency shift key modulated signal modifies a process control signal on a control loop corresponding to said selected one second output without interfering with process control information transmitted over said second control loop corresponding to said selected one second output;

means for removably mounting said second assembly to said second termination board in a manner substantially similar to the manner in which said second plurality of removably mountable intrinsically safe electronic barriers are mounted to said second termination board; and

means for electrically connecting to said apparatus of claim 42 and to a maintenance processor over an RS-485 link.

12. The apparatus of claim 5, further comprising a plurality of said removably mountable intrinsically safe electronic barriers mounted on said termination board.

13. Apparatus mountable onto a termination board for use with a plurality of removably mountable intrinsically safe electronic barriers each of which couples a different microprocessor-equipped smart device in a first area to a process controller in a second area, each smart device generating process control information onto a control loop indicative of a condition in said first area and including means for receiving a maintenance command over said control loop for performing a maintenance operation, said apparatus comprising:

an FSK modem for generating a frequency shift key modulated signal modulated in accordance with a maintenance command to be transmitted to one of said smart devices;

a microprocessor, coupled to said FSK modem, for selecting one of said control loops and causing said frequency shift key modulated signal to be superimposed onto said selected one control loop, wherein said frequency shift key modulated signal modifies a process control signal on said selected one control loop without interfering with process control information transmitted over said selected one control loop; and

a rectangular housing having a connector on one face, said rectangular housing for enveloping and removably mounting said microprocessor and said FSK modem onto said termination board in a manner substantially similar to the manner in which said plurality of removably mountable intrinsically safe electronic barriers are removably mounted onto said termination board.