Electronic condition control system using digital anticipation

• US 4,366,534 A
• Filed: 07/30/1980
• Issued: 12/28/1982
• Est. Priority Date: 07/30/1980
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Kompelien, Arlon D.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US06/173,512
• Time in Patent Office: 881 Days
• Field of Search: 364/118, 364/557, 307/117, 318/596, 318/603, 219/492, 219/494, 236/46 F, 236/46 R, 236/91 R, 236/91 F, 236/91 D, 165/14, 165/26, 235/92 CC, 235/92 CT
• US Class Current: 377/2
• CPC Class Codes: G05B 11/28 using pulse-height modulation; using pulse-width modulation
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A condition control system utilizing digital anticipation involving periodically filling a counter from a relatively high frequency source in response to a first frequency signal. The relatively high frequency signal is fed in a controlled manner into an anticipation cycle counting means to provide for digital anticipation in a condition control system. The system has been specifically disclosed as a temperature control system or thermostat. The system also provides for a bypass means to reset the system when a set point change has been made. A degulping circuit has been provided to eliminate instability at very high and very low loads.

Claims

1. An electronic condition control system using digital anticipation circuit means, including:

frequency source means supplying a plurality of different frequency signals;

timing function signal generator means connected to said frequency source means and generating a plurality of timing signals;

bridge means including condition responsive impedance means;

said bridge means being connected to a first of said frequency signals so that said bridge means has a repetitively cycling output signal at an output means;

comparator means having an input connected to said bridge output means;

said bridge output signal controlling said comparator means to provide a comparator means output signal;

digital logic means connected to said comparator means output and to a first of said timing signals to provide a first digital control signal;

anticipation cycle counter means capable of counting a plurality of digital pulses to establish an anticipation time for said condition control system;

said anticipation cycle counter means having input gate means and output gate means;

said output gate means connected to control bistable output means which establishes "on" and "off" states for said condition control system;

further digital logic means connected to receive said first digital control signal, said first signal frequency, and the state of said bistable output means as control inputs;

said further digital logic means having an output connected to said input gate means of said anticipation cycle counter means; and

said frequency source means further having a relatively high frequency signal compared to said first frequency signal with said relatively high frequency signal connected to said anticipation cycle counter input gate means to cause said counter means to rapidly fill with counts when said counter input gate means is opened by the presence of a signal from said further digital logic means.

2. An electronic condition control system as described in claim 1 wherein the controlled condition is temperature, and said condition responsive impedance means includes a temperature responsive resistor.

3. An electronic condition control system as described in claim 2 wherein said frequency source means includes an oscillator and a plurality of counting stages to divide the frequency of said oscillator to supply said plurality of different frequency signals.

4. An electronic condition control system as described in claim 3 wherein said first frequency signal is in the order of one hertz and said relatively high frequency signal is at least in the order of a magnitude higher than said first frequency signal.

5. An electronic condition control system as described in claim 4 wherein said relatively high frequency signal is in the order of 256 hertz.

6. An electronic condition control system as described in claim 3 wherein said anticipation cycle counter means includes a plurality of counting stages connected to provide for counting of digital signals from said input gate means, and which stages include reset gate means to restore said counter means to its initial state upon receipt of a reset signal.

7. An electronic condition control system as described in claim 6 wherein said digital logic means includes an Exclusive-OR gate, and said further digital logic means includes a plurality of gate means forming a pair of generally parallel but reciprocally controlled signal processing paths.

8. An electronic condition control system as described in claim 7 wherein said timing function signal generator means generates a second of said timing signals;

said second timing signal being of short duration and occurring after said first timing signal; and

counter bypass means responsive to said timing signals and connected to said anticipation counter output means to change the state of said bistable output means upon the existence of a predetermined difference in the temperature relationship between said bridge means and the output state of said control system.

9. An electronic condition control system as described in claim 8 wherein said counter bypass means includes an AND gate and a delay counter;

said delay counter acting to delay the action of said counter bypass means to prevent interference counts from changing the state of said control system.

10. An electronic condition control system as described in claim 9 wherein said delay counter includes reset means to periodically clear said delay counter.

11. An electronic condition control system as described in claim 10 wherein said first frequency signal is in the order of one hertz and said relatively high frequency signal is at least in the order of a magnitude higher than said first frequency signal.

12. An electronic condition control system as described in claim 11 wherein said relatively high frequency signal is in the order of 256 hertz.

13. An electronic condition control system as described in claim 3 which further includes degulping logic means having an output connected to said anticipation cycle counter output means;

said degulping logic means having input gate means connected to said first timing signal and to the output of said further digital logic means;

said degulping logic means acting to disable said anticipation counter means output while concurrently allowing said relatively high frequency signal means to fill said anticipation cycle counter means to prepare said control system to change control states.

14. An electronic condition control system as described in claim 13 wherein said anticipation cycle counter means includes a plurality of counting stages connected to provide for counting of digital signals from said input gate means, and which stages include reset gate means to restore said counter means to its initial state upon receipt of a reset signal.

15. An electronic condition control system as described in claim 14 wherein said digital logic means includes an Exclusive-OR gate, and said further digital logic means includes a plurality of gate means forming a pair of generally parallel but reciprocally controlled signal processing paths.

16. An electronic condition control system as described in claim 15 wherein said first frequency signal is in the order of one hertz and said relatively high frequency signal is at least in the order of a magnitude higher than said first frequency signal.

17. An electronic condition control system as described in claim 15 wherein said relatively high frequency signal is in the order of 256 hertz.