THERMALLY CONTROLLED DUTY CYCLE REGULATION IN AN RFID MODULE

• US 20100308973A1
• Filed: 06/03/2009
• Published: 12/09/2010
• Est. Priority Date: 06/03/2009
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Sandler, Robert I., Strzelczyk, Martin J., Bellows, David E.
• Granted Patent: US 8,199,015 B2
• Time in Patent Office: Days
• US Class Current: 340/10.3
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10207 parameter settings related to power consumption of the interrogator

Abstract

A system and methods for measuring the temperature of an RFID reader module and inserting a delay in the RFID reader'"'"'s duty cycle to prevent the RFID reader from initiating a thermal shutdown. The system and methods are self-adaptable, therefore incurring the benefit regardless of the design of the RFID reader host and its associated heat sink. The system and methods also provide for archiving the collected data and analyzing the data providing the ability to improve the design of the RFID reader host.

Claims

1. A computer-readable media encoded with a computer program for a system for preventing thermal shutdown of an RFID reader by automatically adjusting the duty cycle of the RFID reader, the system comprising:

a temperature measurement component for determining the temperature of the RFID reader; and

a control component for providing a duty cycle delay value storage location, calculating the duty cycle delay value based on the measured temperature and delaying the duty cycle based on the calculated delay value.

2. The system of claim 1, the temperature measurement component comprises a thermocouple for measuring the RFID reader temperature.

3. The system of claim 1, the temperature measurement component comprises a thermistor circuit for measuring the RFID reader temperature.

4. The system of claim 1, the system further comprises a second temperature measurement component for determining the RFID reader ambient temperature.

5. The system of claim 4, the system further comprises an analysis component for calculating an adjustment to the calculated duty cycle delay value based on the determined ambient temperature.

6. The system of claim 5, the analysis component further comprises an artificial intelligence engine for predicting a new duty cycle delay value based on historical duty cycle delay value trends.

7. The system of claim 1, the control component comprises a delay loop integrated into a PID loop for proportionally delaying the RFID reader duty cycle.

8. The system of claim 7, the delay loop comprises decrementing a counter a duty cycle delay value number of times for the calculated delay time.

9. The system of claim 1, the delay loop comprises programming a timer with a duty cycle delay value time and waiting for notification of timer completion before continuing the RFID reader duty cycle.

10. The system of claim 1, the system further comprises a storage component for archiving temperature data.

11. A method for preventing thermal shutdown of an RFID reader component, the method comprising:

employing a processor to execute the following computer executable acts stored on a computer readable medium;

receiving a read RFID tag command from a host device;

measuring the temperature of the RFID reader;

calculating a duty cycle delay value based on the measured temperature;

reading data from an RFID tag; and

delaying the duty cycle based on the calculated delay value.

12. The method of claim 11, further comprising measuring the ambient temperature and predicting adjustments to the calculated duty cycle delay value based on the ambient temperature value.

13. The method of claim 12, the method further comprises archiving the measured RFID reader temperature data and the measured ambient temperature data to a storage component.

14. The method of claim 13, the method further comprises automatically uploading the archived temperature data to an RFID reader host device based on an event configured on the RFID reader host device and communicated in a command to the RFID reader.

15. The method of claim 14, the event is reaching the maximum storage capacity of the storage component.

16. The method of claim 13, the method further comprises analyzing the archived temperature data and predicting a duty cycle delay value based on the archived temperature data trend.

17. A system for automatically preventing thermal shutdown of an RFID reader component, the system comprising:

means for receiving a read RFID tag command from a host device;

means for measuring the temperature of the RFID reader;

means for calculating a duty cycle delay value based on the measured temperature;

means for reading data from an RFID tag; and

means for adjusting the duty cycle delay based on the calculated delay value.

18. The system of claim 17, further comprising:

means for archiving measured temperature data and duty cycle delay data.

19. The system of claim 17, further comprising:

means for measuring the ambient temperature; and

means for adjusting the calculated duty cycle delay value based on the measured ambient temperature value.

20. The system of claim 18, further comprising:

means for analyzing the archived temperature data and the duty cycle delay data and generating a report based on the thermal efficiency of RFID reader operation; and

means for automatically distributing the generated report to other locations.

21. A method for preventing thermal shutdown of an RFID reader component, the method comprising:

employing a processor to execute the following computer executable acts stored on a computer readable medium;

receiving a read trigger from a host device;

operating the RFID reader at maximum read rate;

measuring the temperature of the RFID reader; and

adding a delay to the duty cycle if the RFID reader temperature approaches a value indicating thermal shutdown before the end of the triggered read.