Calibration

The Weather Report comes pre-calibrated from the factory, but it is possible to recalibrate most of the primary functions of the instrument using TWICAL program.

Barometric Pressure

Normally, barometric pressure is the only item that needs to be recalibrated (adjusting for altitude). The proper local barometric pressure can be obtained from the local news. Set the barometric pressure reading you obtained from the local media by using the calibration mode function.

Temperature

If for some reason you suspect that the temperature is not calibrated properly, use a quality bulb thermometer with which to calibrate the temperature. Remember that the WRL will be most accurate near the temperature at which it was calibrated.

Humidity Sensor Calibration

The humidity sensor is calibrated by inputting two voltages found on the humidity sensor into the WRL. Humidity calibration factors can be entered by depressing select and humdity hold at exacty the same time. The humidity calibration numbers are found on the humidity/temperature sensor and on the back of the instrument console. These calibration numbers are supplied to us by the manufacturer of the sensor and are normally not changed.

Rainfall

The WRL is compatible with most rain collectors on the market today. Actual measurement calibration is accomplished inside the rain collector by adjusting two stainless steel screws.

Setting 0 turns the rainfall counter off. Setting 1 or 2 tells the WRL to react with one count for every momentary switch closure of the rain collector.

Setting 3 tells the WRL to react with one count for every rain collector switch transition from an open or closed state.

The rain measurement value tells the WRL how much rainfall to display for each count.

THE PROPER SETTING FOR THE TEXAS WEATHER INSTRUMENTS RAIN COLLECTOR IS "2" FOR THE COUNT AND ".01" FOR THE MEASUREMENT.

Texas Weather Instruments, Inc.

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WRL Instruction Manual

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Texas Instruments WRL-10 instruction manual Barometric Pressure, Temperature, Humidity Sensor Calibration, Rainfall