Economizer/DCV controller with manual sensor calibration
First Claim
1. A calibrating mechanism for an economizer controller comprising:
- a precision sensor of a first kind for measuring a control parameter of an HVAC system; and
a first system sensor of the first kind for measuring the control parameter of an economizer controller of an HVAC system; and
wherein;
the first system sensor is read to obtain a first value in a first ambient environment at a first time;
the precision sensor is read to obtain a second value in the first ambient environment at the same first time as the first system sensor;
the first value is compared with the second value to obtain a first offset from a difference between the first and second values;
the first system sensor is read to obtain a third value in the first ambient environment at a second time;
the precision sensor is read to obtain a fourth value in the first ambient environment at the same second time as the first system sensor;
the third value of the first system sensor is compared with the fourth value of the precision sensor to obtain a second offset from a difference between the third and fourth values,wherein the first and second offsets are combined to provide a curve of offsets versus values from the first system sensor, which is extrapolated for obtaining offsets for other values obtained by the first system sensor.
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Abstract
An economizer controller with sensor calibration. A controller sensor may be used to measure a parameter. At the same time at the same location of the measurement with the controller sensor, a measurement of the same parameter may be made with a precision sensor. The difference between the two measurements may be saved to a controller memory as an offset. The offset may be used to compensate future measurements of the same parameter by the controller sensor. Additional offsets at various magnitudes may be obtained between the precision and the controller sensors for compensating subsequent measurements by the controller sensor. Measurements with the compensated sensor may be used for calibrating sensors in other economizer controllers, for example, at remote locations in the field.
37 Citations
19 Claims
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1. A calibrating mechanism for an economizer controller comprising:
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a precision sensor of a first kind for measuring a control parameter of an HVAC system; and a first system sensor of the first kind for measuring the control parameter of an economizer controller of an HVAC system; and wherein; the first system sensor is read to obtain a first value in a first ambient environment at a first time; the precision sensor is read to obtain a second value in the first ambient environment at the same first time as the first system sensor; the first value is compared with the second value to obtain a first offset from a difference between the first and second values; the first system sensor is read to obtain a third value in the first ambient environment at a second time; the precision sensor is read to obtain a fourth value in the first ambient environment at the same second time as the first system sensor; the third value of the first system sensor is compared with the fourth value of the precision sensor to obtain a second offset from a difference between the third and fourth values, wherein the first and second offsets are combined to provide a curve of offsets versus values from the first system sensor, which is extrapolated for obtaining offsets for other values obtained by the first system sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for calibrating a system sensor in an economizer controller, comprising:
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measuring a first parameter for controlling an economizer/demand control ventilation system with a system sensor of an economizer controller to get a first reading at each of a plurality of ambient temperatures; measuring the first parameter with a precision sensor to get a second reading at each of the plurality of ambient temperatures; computing a plurality of offsets from a difference between the first and second readings of the first parameter for each of the plurality of ambient temperatures; entering the offsets into a memory of the economizer controller; and using one of the computed plurality of offsets for calibrating another reading from the system sensor of the first parameter; and wherein computing the offsets from the readings of the precision sensor and the system sensor, and calibrating of a subsequent reading of the system sensor are automatically processed; and wherein each of the first and second readings are taken at a same time for each of the plurality of ambient temperatures. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for calibrating a system sensor of an economizer controller, comprising:
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taking a plurality of readings with a system sensor of an economizer controller at a first set of different values of a parameter for controlling an economizer/demand control ventilation system; taking a plurality of readings with a precision sensor at the first set of different values of the parameter for the first set of different values; determining a plurality of offsets wherein each offset is a comparison of a reading from the system sensor and a reading from the precision sensor at a same time, of the parameter for the first set of different values; and compensating a reading from the system sensor of a certain value of the parameter with an offset from the plurality of offsets for a value, of the first set of different values, most closely corresponding to the certain value; and wherein each the plurality of readings with a precision sensor is taken at a same time as a corresponding reading taken with the system sensor. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification