Error detection for HVAC systems

• US 5,555,269 A
• Filed: 10/29/1993
• Issued: 09/10/1996
• Est. Priority Date: 10/29/1993
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Friday, Arthur F. Jr., Chan, Chi-Ping
• Primary Examiner(s): Ramirez, Ellis B.
• Assistant Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US08/143,038
• Time in Patent Office: 1,047 Days
• Field of Search: 371/5.1, 364/514, 364/265, 364/153, 364/154, 364/162, 364/185, 165/13, 62/132
• US Class Current: 714/704
• CPC Class Codes: G05B 19/0425 Safety, monitoring

Abstract

A process is disclosed for checking communications that a controller receives from elements in an HVAC system. The process includes storing the communications and thereafter checking each stored communication against a range of permitted values for that particular communication. The thus checked communication is made available for use by the controller only if it is within the range of permitted values. A count of times that a particular element does not comply with the check is maintained with a warning being generated in the event that the element continues to communicate unacceptable signal values.

Claims

1. A process executable by a processor within a control unit of a heating or cooling system, the processor being responsive to values of electronic signals received from elements of a heating or cooling system electronically connected to the control unit, said process comprising the steps of:

storing an electronic signal value of an electronic signal received from at least one particular electronically connected element in a storage location set aside within a memory associated with the processor for storing the value of electronic signal received from the particular element;

comparing the stored value of the electronic signal received from the particular element with a range of electronic signal values permitted for the particular element;

transferring the stored value of the electronic signal received from the particular element to a different storage location when the stored value of the electronic signal received from the particular element is within the range of permitted electronic signal values for the particular element; and

using the value of the electronic signal received from the particular element within a control program executable by the processor so as to control the heating or cooling system only when the value of the electronic signal received from the particular element has been transferred to the different storage location for use within the control program.

2. The process of claim 1 wherein said step of comparing the stored value of the electronic signal received from the particular element with a range of permitted electronic signal values for the particular element comprises the steps of:

accessing the maximum and minimum values permitted for the electronic signal received from the particular element; and

comparing the value of the electronic signal received from the particular element with the maximum and minimum electronic signal values permitted for the electronic signal received from the particular element.

3. The process of claim 1 further comprising the steps of:

noting when the comparing step indicates that a stored value of the electronic signal received from the particular element is not within the range of permitted electronic signal values for the particular element; and

exiting from the process without triggering said step of transferring the stored value of electronic signal received from the particular element.

4. The process of claim 1 wherein said step of storing an electronic signal value of an electronic signal received from at least one particular electronically connected element and said step of comparing the stored value of the electronic signal received from the particular element are repeated and wherein said process further comprises the step of:

counting the number of successive comparisons made of the stored electronic signal value of the electronic signal received from the particular element that indicate the value of the electronic signal received from the particular element is not within the range of permitted electronic signal values for the particular element.

5. The process of claim 4 further comprising:

generating a warning when the count of successive comparisons made of the stored values of the electronic signal received from the particular element reaches a predetermined number.

6. The process of claim 1 wherein the the control program includes a plurality of control variables that are related to the elements of the heating or cooling system electronically connected to the control unit and wherein said step of transferring the stored value of the electronic signal received from the particular element to a different storage location comprises the steps of:

identifying a control variable that is related to the particular element; and

transferring the value of the electronic signal received from the particular element to a storage location associated with the identified control variable for subsequent use by the control program when the stored value of the electronic signal received from the particular element is within the range of permitted electronic signal values for the particular element.

7. The process of claim 6 wherein said step of comparing the stored value of electronic signal received from the particular element with a range of electronic signal values permitted for the particular element comprises:

identifying a control variable that is related to the particular element;

accessing the maximum and minimum values permitted for the electronic signal received from the particular element from storage locations associated with the identification of the control variable; and

comparing the value of the electronic signal received from the particular element with the accessed maximum and minimum values for the electronic signal received from the particular element.

8. The process of claim 7 wherein said step of storing an electronic signal value of an electronic signal received from at least one particular electronically connected element and said step of comparing the stored value of the electronic signal received from the particular element are repeated and wherein said process further comprises the steps of:

noting when the comparing step indicates that a stored value is not within the range of permitted electronic signal values for the element; and

exiting from the process without triggering said step of transferring the previously stored value of electronic signal received from the particular element.

9. The process of claim 7 further comprising the step of:

counting the number of successive comparisons made of the stored electronic signal value of the electronic signal received from the particular element that indicate the value of the electronic signal received from the particular element is not within the range of permitted electronic signal values for the particular element.

10. The process of claim 9 further comprising the step of:

generating a warning when the count of successive comparisons made of the stored value of the electronic signal received from the particular element reaches a predetermined number.

11. The process of claim 7 wherein the plurality of control variables are related to the elements electronically connected to the control unit by configuration data stored for use by the processor and wherein said step of identifying a control variable that is related to the particular element comprises the step of:

accessing the configuration data to identify the particular control variable that is related to the particular element.

12. The process of claim 6 wherein the processor receives electronic signal values from the electronically connected elements via identifiable communication channels and wherein said step of storing an electronic signal value of an electronic signal received from a particular element in a storage location set aside within a memory associated with the processor for storing the value of the electronic signal received from the particular element comprises the steps of:

identifying the communication channel for the particular element; and

storing the value of the electronic signal received from the particular element in a storage location associated with an identification of the communication channel.

13. The process of claim 6 wherein the plurality of control variables are related to the elements electronically connected to the control unit by configuration data stored for use by the processor and wherein said step of identifying a control variable that is related to the particular element comprises the step of:

accessing the configuration data to identify the particular control variable that is related to the particular element.

14. The process of claim 6 wherein the elements of the heating or cooling system electronically connected to the control unit include temperature sensors and wherein the electronic signal value that is stored, compared and transferred is a temperature value and wherein the control variable that is identified is a temperature variable within the control program that is used by the control program to compute values of other control variables dependent on the value of the temperature variable.

15. The process of claim 1 further comprising the step of:

using within the control program a value presently stored in the different storage location when the value of the electronic signal stored in the storage location set aside within the memory associated with the processor is not within the range of permitted electronic signal values for the particular control element.