Transmitter for transmitting on a two-wire transmitting line

• US 4,806,905 A
• Filed: 10/01/1986
• Issued: 02/21/1989
• Est. Priority Date: 10/01/1986
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: McGowan, David L. III, Oxenberg, Steven M.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/914,031
• Time in Patent Office: 874 Days
• Field of Search: 340/310 R, 340/310 A, 340/870.39, 340/870.40, 340/825.06, 340/870.16, 340/870.18, 375/5, 375/7, 375/24, 375/36
• US Class Current: 340/870.18
• CPC Class Codes: G08C 19/02 in which the signal transmitted is magnitude of current or voltage G08C19/36, G08C19/38 take precedence

Abstract

A transmitter for repeatedly transmitting a measured value in the form of a digital signal through a two-wire transmission line, includes a receiving unit for receiving a digital command signal from a communicator through the two-wire transmission line, and a processor for sending out a response signal in response to the command signal upon reception thereof. The measured value is sent using a newest measured value after repetitive transmission of the measured value is interrupted. The measured value is transmitted from the transmitter by a change in current supplied to the two-wire transmission line, and reception of the command signal is performed by a change in interline voltage of the two-wire transmission line.

Claims

1. A transmitter for transmitting a measured value of a process variable in the form of a digital signal through a two-wire transmission line by a change in a current in the two-wire transmission line comprising

means for receiving a digital command signal supplied through said two-wire transmission line and

control means for adding the measured value to a digital response signal generated in response to the digital command signal and for transmitting a resultant digital signal so as to transmit on the two-wire transmission line at least one measured value within a predetermined time period.

2. A transmitter according to claim 1 wherein the measured value is sent as a newest measured value after the transmission of the measured value is interrupted for said predetermined time period.

3. A transmitter according to claim 1 wherein the reception of the command signal utilizes a change in an interline voltage of said two-wire transmission line.

4. A transmitter according to claim 1 and including means for monitoring said predetermined period comprising a timer.

5. A transmitter according to claim 1 wherein said control means comprises a digital processor.

6. A transmitter for repeatedly transmitting a measured value of a process variable in the form of a digital signal through a two-wire transmission line by a change in a current in the two-wire transmission line comprising

means for receiving a digital command signal supplied through said two-wire transmission line and

control means for adding the measured value to a digital response signal generated in response to the digital command signal and for repeatedly transmitting a resultant digital signal so as to transmit on the two-wire transmission line at least one measured value within a predetermined time period.

7. A transmitter according to claim 6 wherein the measured value is sent as a newest measured value after the repetitive transmission of the measured value is interrupted for said predetermined time period.

8. A transmitter according to claim 6 wherein the reception of the command signal utilize a change in an interline voltage of said two-wire transmission line.

9. A transmitter according to claim 6 and including means for monitoring said predetermined period comprising a timer.

10. A transmitter according to claim 6 wherein said control means comprises a digital processor.

11. A transmitter for transmitting a measured value of a process variable in the form of a digital through a two-wire transmission line by a change in a current in the two-wire transmission line comprising

means for receiving a digital command signal supplied through said two-wire transmission line,

means for digitally transmitting on said transmission at least one measured value of the process variable within a predetermined time period and

control means for adding the measured value to a response signal generated in response to the digital command signal and for transmitting a resultant digital signal on said transmission line.

12. A transmitter according to claim 11 wherein the measured value is sent as a newest measured value after the transmission of the measured value is interrupted for said predetermined time period.

13. A transmitter according to claim 11 wherein the reception of the command signal utilizes a change in an interline voltage of said two-wire transmission line.

14. A transmitter according to claim 11 and including means for monitoring a predetermined period comprising said time.

15. A transmitter according to claim 11 wherein said control means comprises a digital processor.