DYNAMICALLY ADJUSTED A/D RESOLUTION
First Claim
1. A method of controlling an analog-to-digital (A/D) converter in a process variable transmitter that converts an analog input signal indicative of an industrial process variable to a digital output signal, the method comprising:
- receiving the analog input signal indicative of the industrial process variable;
measuring a signal level of the analog input signal;
intermittently matching a resolution setting for the A/D converter to the measured signal level for the analog input, based on the measured signal level for the analog input signal, such that the A/D converter converts the analog input signal to the digital output signal with a highest resolution obtainable from the A/D converter, given the measured signal level of the analog input signal;
converting the analog input signal to the digital output signal using the matched resolution setting; and
sending information related to the industrial process variable over a transmission connection.
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Accused Products
Abstract
A process variable transmitter is used to measure a process variable, and, in doing so, dynamically changes the resolution of the A/D converter based upon the measured value of the analog input signal. This can be done by automatically adjusting the configurable resolution gain adjustment based on the value of the analog signal being measured, by normalizing the input signal being measured so that it is centered in an optimal resolution window of the A/D converter, or by adjusting a voltage reference provided to the A/D converter.
13 Citations
20 Claims
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1. A method of controlling an analog-to-digital (A/D) converter in a process variable transmitter that converts an analog input signal indicative of an industrial process variable to a digital output signal, the method comprising:
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receiving the analog input signal indicative of the industrial process variable; measuring a signal level of the analog input signal; intermittently matching a resolution setting for the A/D converter to the measured signal level for the analog input, based on the measured signal level for the analog input signal, such that the A/D converter converts the analog input signal to the digital output signal with a highest resolution obtainable from the A/D converter, given the measured signal level of the analog input signal; converting the analog input signal to the digital output signal using the matched resolution setting; and sending information related to the industrial process variable over a transmission connection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A process variable transmitter that receives a sensor input signal from a sensor that senses a process variable and provides the sensor input signal at an analog signal level indicative of the process variable, comprising:
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an analog-to-digital (A/D) converter that converts the sensor input signal to a digital value at a resolution, wherein the resolution obtainable by the A/D converter changes according to a predetermined relationship between the analog signal level of the sensor input signal and a reference voltage provided to the A/D converter; and a processor, coupled to the VD converter, receiving the digital value and transmitting information over a process control loop based on the digital value, the processor providing a resolution control signal to control the resolution at which the A/D converter provides the digital value by changing at least one of the analog signal level of the sensor input signal or the reference voltage, to match the resolution to the analog signal level of the sensor input signal so the A/D converter provides the digital value at a predetermined resolution, given the analog signal level of the sensor input signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method of controlling a process variable transmitter, the method comprising:
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receiving, from a sensor, an analog input signal indicative of an industrial process variable; measuring a signal level of the analog input signal by using an analog-to-digital (A/D) converter that converts the analog input signal to a digital output signal; varying a resolution setting for the A/D converter, based on the measured signal level for the analog input, to configure the A/D converter to convert the analog input signal to the digital output signal with a highest resolution obtainable from the A/D converter, given the measured signal level of the analog input signal; converting the analog input signal to the digital output signal using the varied resolution setting; and sending information related to the industrial process variable over a transmission connection comprising one of a hardwired process control loop and a wireless connection. - View Dependent Claims (20)
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Specification