METHOD AND APPARATUS FOR DETERMINING CHARACTERISTICS OF AN INPUT SIGNAL

• US 20150331027A1
• Filed: 12/20/2012
• Published: 11/19/2015
• Est. Priority Date: 12/20/2012
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Inventors: Mearns, Brian Patrick
• Granted Patent: US 10,488,449 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 23/10 by converting frequency into a train of pulses, which are then counted , i.e. converting the signal into a square wave

Abstract

Aspects are directed to systems and methods of determining a value of a characteristic related to timing between sequential events of an input electronic signal using an input capture counter having a maximum counting value, the input electronic signal having an expected variable period between events whose value is between a maximum period value and a minimum period value with a delta period value equal to a difference between the maximum period value and the minimum period value.

Claims

1. A method of determining a value of a characteristic related to timing between sequential events of an input electronic signal using an input capture counter having a maximum counting value, the input electronic signal having an expected variable period between events whose value is between a maximum period value and a minimum period value with a delta period value equal to a difference between the maximum period value and the minimum period value, the method comprising:

receiving the electronic signal;

setting a counter rate of the input capture counter to a value equal to the maximum counting value divided by the delta period value;

detecting a first capture event;

determining a value of the input capture counter at the first capture event;

detecting a second capture event;

determining a value of the input capture counter at the second capture event; and

determining the value of the characteristic related to timing based on the value of the input counter at the first capture event and the value of the input counter at the second capture event.

2. The method of claim 1, wherein the characteristic related to timing is at least one of period, frequency, or elapsed time.

3. The method of claim 1, wherein receiving an electronic signal includes receiving input AC power having a voltage waveform, and wherein the value of the characteristic related to timing is a period of the voltage waveform of the input power.

4. The method of claim 1, wherein detecting the first capture event includes detecting one of:

a rising edge of the electronic signal,

a falling edge of the electronic signal, and

a threshold value of the electronic signal.

5. The method of claim 3, further comprising determining an RMS voltage of the voltage waveform based on voltage samples which are synchronized based on the period of the voltage waveform of the input power.

6. The method of claim 1, further comprising detecting that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value.

7. The method of claim 6, further comprising:

adjusting, based on detecting that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value, the minimum period value and the maximum period value.

8. The method of claim 7, further comprising:

adjusting the counter rate of the input capture counter in response to detecting that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value.

9. The method of claim 1, further comprising:

using a second input capture counter operating at a counter rate less than the counter rate of the input capture counter;

detecting an out of range period for the electronic signal based on a counter value from the second input capture counter; and

based on detecting the out of range period, adjusting the counter rate of the input capture counter.

10. A system comprising:

an input configured to receive an input signal with events having an expected variable period between a maximum period value and a minimum period value with a delta period value equal to a difference between the maximum period value and the minimum period value;

a capture device coupled to the input and configured to detect at least one characteristic of the input signal;

a counter having a counter rate and a maximum counting value;

a controller coupled to the capture device and the counter and configured to;

set a counter rate of the counter to a value equal to the maximum counting value divided by the delta period value;

detect a first capture event based on receiving a signal from the capture device;

determine a value of the counter at the first capture event;

detect a second capture event based on receiving a signal from the capture device;

determine a value of the input counter at the second capture event; and

determine the value of the characteristic related to timing based on the value of the input counter at the first capture event and the value of the input counter at the second capture event.

11. The system of claim 10, wherein the characteristic related to timing is at least one of period, frequency, or elapsed time.

12. The system of claim 10, wherein the input is an AC power input of the system and wherein the input signal is a voltage waveform of input AC power.

13. The system of claim 10, wherein the capture device is configured to detect at least one of:

a rising edge of the input signal,

a falling edge of the input signal, and

a threshold value of the input signal.

14. The system of claim 12, wherein the controller is further configured to determine an RMS voltage of the input voltage waveform based on voltage samples which are synchronized based on the value of the characteristic related to timing.

15. The system of claim 10, wherein the controller is further configured to detect that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value.

16. The system of claim 15, wherein the controller is further configured to adjust, based on detecting that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value, the minimum period value and the maximum period value.

17. The system of claim 16, wherein the controller is further configured to adjust the counter rate of the counter in response to detecting that the period of the electronic signal is outside of a range between the maximum period value and the minimum period value.

18. The system of claim 10, further comprising:

a second counter coupled to the controller and configured to operate at a counter rate less than the counter rate of the counter;

wherein the controller is configured to detect an out of range period for the electronic signal based on a counter value from the second counter, and based on detecting the out of range period, adjust the counter rate of the counter.

19. A system comprising:

an input configured to receive an input signal with events having an expected variable period between a maximum period value and a minimum period value with a delta period value equal to a difference between the maximum period value and the minimum period value;

a counter having a counter rate and a maximum counting value, the counter rate being configured to be equal to the maximum counting value divided by the delta period value; and

means for detecting a first capture event and a second capture event of the input signal, determining a value of the counter at the first capture event and the second capture event, and determining the value of the characteristic related to timing based on the value of the input counter at the first capture event and the value of the input counter at the second capture event.

20. The system of claim 19, further comprising means for detecting an out of range period of the input signal, and in response adjusting the counter rate of the counter.