Refrigeration control apparatus and method

• US 6,711,445 B1
• Filed: 04/30/1999
• Issued: 03/23/2004
• Est. Priority Date: 12/17/1998
• Status: Expired due to Fees

• Current Assignee: Danfoss Company Limited (Bitten Og Mads Clausens Fond)
• Original Assignee: Danfoss Company Limited (Bitten Og Mads Clausens Fond), Kysor/Warren
• Inventors: Heath, Richard, Rader, Roy M., Pellerin, Henry Robert, Friedlander, Paul
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): FRANK, ELLIOT L
• Application Number:
  US09/302,907
• Time in Patent Office: 1,789 Days
• Field of Search: 700/2, 700/3, 700/9, 700/12, 621/26, 621/27, 621/75
• US Class Current: 700/3
• CPC Class Codes: F25D 29/00 Arrangement or mounting of control or safety devices
• CPC Class Codes: G05B 9/02 electric

Abstract

A refrigeration control apparatus comprises a master unit with a mother board. The mother board comprises a bus configured to carry signals between boards coupled to the mother board. A processor board interfaced to the mother board is provided. The processor board comprises a processor, and a program memory where instructions for the processor are stored on the program memory. An interface circuit coupled to the mother board is provided. A load control module interfaced to the mother board is provided, wherein the load control module comprises an interface circuit coupled to the mother board, and a circuit breaker coupled to a power input. A load relay comprising a first interlocked relay and a second interlocked relay coupled to the circuit breaker is provided. The load relay is configured to switch power. An override switch and the processor coupled to the load relay to control the load relay is provided. Furthermore, an indicator coupled to the processor and the override switch is provided, wherein the line voltage being removed from the second interlocked relay when the first interlocked relay is actuated.

Claims

1. An arrangement within a refrigeration control apparatus comprising

a master unit comprising

a mother board comprising

a bus configured to carry signals between boards coupled to the mother board;

a processor board interfaced to the mother board, the processor board comprising

a processor;

a program memory;

instructions for the processor stored on the program memory;

an interface circuit coupled to the mother board;

a load control module interfaced to the mother board, the load control module comprising

an interface circuit coupled to the mother board;

a circuit breaker coupled to a power input;

a load relay comprising a first interlocked relay and a second interlocked relay coupled to the circuit breaker, the load relay configured to switch power;

an override switch and the processor coupled to the load relay to control the load relay; and

an indicator coupled to the processor and the override switch;

wherein line voltage being removed from the second interlocked relay when the first interlocked relay is actuated.

2. The arrangement of claim 1 further comprising

a slave unit coupled to the master unit comprising

a mother board; and

a load control module.

3. The arrangement of claim 1 further comprising

a communications circuit coupled to the processor.

4. The arrangement of claim 3 wherein

the communications circuit comprises a serial communications circuit.

5. The arrangement of claim 3 wherein

the communications circuit comprises a network communications circuit.

6. The arrangement of claim 3 wherein

the communications circuit comprises a serial communications circuit and a network communications circuit.

7. The arrangement of claim 3 further comprising

a rack controller interfaced to the master unit through the communications circuit.

8. The arrangement of claim 1 wherein

the override switch has a first position and a second position;

the first interlocked relay being actuated when the override switch is in the first position; and

the second interlocked relay being actuated when the override switch is in the second position.

9. The arrangement of claim 1 wherein

the override switch has a third position;

the first interlocked relay and the second interlocked relay being under the control of the processor when the override switch is in the third position.

10. The arrangement of claim 1 wherein

the indicator provides a first indication when the override switch is in the first or second positions;

the indicator provides a second indication when the override switch is in the third position and the first interlocked relay is actuated; and

the indicator provides a third indication when the override switch is in the third position and the second interlocked relay is actuated.

11. The arrangement of claim 1 wherein

the load control module comprises a circuit interface module configured to be coupled to one or more loads comprising one or more selected from the group consisting of a coil on a refrigeration valves and a coil on a defrost contactor.

12. The arrangement of claim 1 wherein

the load control module comprises a compressor module configured to be coupled to one or more loads comprising a coil on a compressor contactor.

13. The arrangement of claim 1 further comprising

a fault circuit configured to detect the occurrence of a fault and report it to the processor board;

the processor configured to illuminate a fault indicator upon the occurrence of the fault.

14. The arrangement of claim 13 further comprising

a fault reset switch coupled to the processor board;

and

the processor board being configured to stop illuminating the fault indicator when the fault reset switch is activated.

15. The arrangement of claim 1 further comprising

a fault circuit configured to detect the occurrence of one or more of a plurality of faults and report the existence of one or more faults and the identity of the one or more faults to the processor board;

the processor configured to report the identity of the one or more faults to a rack controller.