US 5,708,589 A · Error recovery system for an energy controller for an electric water heater

Abstract

A data protection and recovery system for an energy controller for a water heater is disclosed. The energy controller is a microprocessor based system which includes a central processing unit, volatile and non-volatile memories, and a clock. It functions to energize the water heater only during a certain period of the day. During normal operation of the system, the system uses the volatile memory as a workspace, and normally copies data in the volatile memory to the non-volatile memory. The system senses electrical disturbances, such as power surges, and prevents the writing of any data to the non-volatile memory components during the electrical disturbance. After the electrical disturbance subsides, the system checks the integrity of the data written to the volatile memory, and if it was not corrupted by the electrical disturbance, the data is then written to the non-volatile memory. If the data in the volatile memory was corrupted by the electrical disturbance, the system copies the data from the non-volatile memory to the volatile memory, and the system is restarted.

Claims14

Dependent claims

A method for protecting the data of and recovering from data errors in an energy controller for an electric water heater, said energy controller comprising a central processing unit (CPU) logically connected to a random access memory (RAM), an electronically erasable programmable read only memory (EEPROM), and a clock with a small amount of memory, comprising the steps of:

initiating a blocking phase upon the start up of said energy controller;
monitoring the power supply to said energy controller for electrical disturbance;
initiating said blocking phase upon the detection of a disturbance in said power supply;
preventing said CPU from writing to said EEPROM and said clock during said blocking phase;
copying the contents of said EEPROM to said RAM after initiating said blocking phase;
performing an error check on the contents of said RAM;
performing a validity check on the contents of said clock;
copying the contents of said RAM to said EEPROM after said blocking phase in the event that no error occurred;
and
restoring said clock from said clock memory if an error is detected in said clock.

7 more elements

A system for protecting the data of and recovering from data errors in an energy controller for an electric water heater comprising:

a central processing unit;
an electronically erasable programmable read only memory logically connected to said central processing unit, said electronically erasable programmable read only memory containing information used for the operation of said system;
a random access memory logically connected to said central processing unit, said random access memory containing a copy of said information from said electronically erasable programmable read only memory;
a clock with a small amount of memory logically connected to said central processing unit;
a power switch logically connected to said central processing unit;
a power failure detector logically connected to said central processing unit;
a power supply to supply power to said central processing unit, said electronically erasable programmable read only memory, said random access memory, said clock, said power failure detector, and said electric switch;
external inputs logically connected to said central processing unit;
and
an electric water heater connected to said power supply through said switch;
said central processing unit utilizing said information in said random access memory to close said electric switch thereby allowing the thermostatic supply of energy to said water heater, and said central processing unit utilizing said information in said random access memory to open said electric switch thereby cutting off power to said water heater;
said central processing unit updating said electronically erasable programmable read only memory with data from said RAM when not in a blocking phase;
and
said central processing unit entering said blocking phase in response to a disturbance in said power supply.

11 more elements

Dependencies are inferred from the claim text.

Error recovery system for an energy controller for an electric water heater

Life of this patent

Error recovery system for an energy controller for an electric water heater

Life of this patent

Abstract

Claims14