SYSTEM RECOVERY IN A HEATING, VENTILATION AND AIR CONDITIONING NETWORK

• US 20100106315A1
• Filed: 10/21/2009
• Published: 04/29/2010
• Est. Priority Date: 10/27/2008
• Status: Active Grant

• Current Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Original Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Inventors: Grohman, Wojciech
• Granted Patent: US 8,255,086 B2
• Time in Patent Office: Days
• US Class Current: 700/276
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: H04L 12/2803 Home automation networks
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route

Abstract

The disclosure provides various embodiments of systems and methods of generating a heartbeat in an HVAC system and networks. In an embodiment, a method includes a heartbeat message being sent by a first subnet controller upon the first subnet controller taking active control of a subnet of the HVAC network. The active heartbeat message timer is reset. Another heartbeat message is sent if a specified amount of time has elapsed since a previous heartbeat message was sent by said heartbeat generator.

Claims

1. A method of generating a heartbeat message in an HVAC network, comprising:

sending a heartbeat message by a first subnet controller upon said first subnet controller taking active control of a subnet of said HVAC network;

resetting an active heartbeat message timer; and

sending another heartbeat message if a specified amount of time has elapsed since a previous heartbeat message was sent by said heartbeat generator.

2. The method claim 2, furthermore comprising sending another heartbeat message if said first subnet controller has detected a device start-up message on said subnet;

3. The method of claim 2, wherein any step of sending another heartbeat message resets said active message heartbeat timer.

4. The method of claim 2, wherein a count on said heartbeat timer is incremented with a passage of time.

5. A method of detecting a heartbeat in an HVAC network, comprising:

determining if a first subnet controller on a subnet has provided a heartbeat message within a first specified time frame;

wherein

if said first subnet controller has provided said heartbeat message within said first specified time frame;

a second, inactive controller on said subnet stays in an inactive state; and

wherein

if said first subnet controller has not provided said heartbeat message within said specified time frame;

said second, inactive subnet controller on said subnet transitions into an active state for said subnet of said HVAC network.

6. The method of claim 5, wherein said selected time is substantially three minutes.

7. The method of claim 5, further comprising:

determining whether a device on said subnet detects said heartbeat message within a second specified time frame;

wherein

if said device has detected said heartbeat message within said second specified time frame, said device continues to operate in a prior mode; and

if said device has not detected said heartbeat message within said second specified time frame, said device;

a) issues a heartbeat-message-missing alarm;

b) ceases to operate in a communication mode; and

c) continues to generate device status messages.

8. The method of claim 7, wherein said selected time is substantially three minutes.

9. A HVAC network that can detect and generate a heartbeat, comprising:

a first subnet controller on a subnet of said HVAC network;

a second, inactive, subnet controller on said subnet configured to determine if said first subnet controller has provided a heartbeat message within a first specified time frame;

wherein if said first subnet controller has provided said heartbeat message, said second subnet controller stays in its inactive state; and

wherein if said first subnet controller has not provided said heartbeat message, said second, inactive controller transitions starts an arbitration process with other inactive controllers on the subnet that leads into an active subnet startup state for said subnet of said HVAC network.

10. The system of claim 9, wherein said first specified time frame is substantially three minutes.

11. The system of claim 9, further comprising:

a device on said subnet configured to detect a heartbeat message within a second specified time frame, wherein

if said device has detected said heartbeat message, said device continues to operate in a prior mode; and

if said device has not detected said heartbeat message, said device is configured to;

a) issue a heartbeat-message-missing alarm;

b) cease to operate in a communication mode; and

c) continue to generate device status messages.

12. The system of claim 11, wherein said selected time is substantially three minutes.

13. The system of claim 9, further comprising:

a heartbeat message timer, and

a heartbeat generator configured to;

a) generate a heartbeat message by a first subnet controller upon said first subnet controller taking active control of a subnet of said HVAC network;

b) send another heartbeat message if said subnet controller has detected a subnet controller message on said subnet from a second subnet controller;

c) send another heartbeat message if said subnet controller has detected a device message on its subnet; and

d) send another heartbeat message if a specified amount of time has elapsed since a previous heartbeat message has been generated by said heartbeat generator.

14. The first subnet controller of claim 13, wherein said message heartbeat timer is reset by any step of sending another heartbeat message.

15. The first subnet controller of claim 13, wherein said heartbeat timer increments with a passage of time.

16. The first subnet controller of claim 13, wherein said specified amount of time is substantially one minute.

17. The system of claim 11, further comprising a field-programmable device to be used in said HVAC network, comprising:

at least two field pins configured to be shorted together;

a field system feature selector;

a processor coupled to;

a) said field dependent feature selector, and

b) said at least two field pins,

wherein said processor can read a plurality of shorts between two said pins and an output of said field system feature selector, to generate a value; and

an LED coupled to said processor configured to display said value.

18. The field-programmable device of claim 17, wherein said processor can further:

read a duration of a short of a first selected time period to enable a presentation of values for a selected dependent feature; and

present an increment of said value when said first and second field pins are shorted together for said second time.

19. The field programmable device of claim 17, wherein said feature is selected from a group including:

a) a unit capacity, and

b) a model number.

20. The field programmable device of claim 17, wherein said value is presented to a user with said LED.