Texas Instruments Weather Report Logger WRL-25 Manual page 20

WRL Instruction Manual
Note: The WRL has two separate minimum and maximum memories. Clearing the M command
minimum and maximum memory will not affect the C command minimum and maximum memory
and vice- versa. The printer/computer memories clear at 12:00 midnight every day and/or when the
c key is pressed on the computer console.
Calibration Reference
The Weather Report comes pre-calibrated from the factory, but it is possible to recalibrate most of
the primary functions of the instrument using the F5 function of the TWI_LOG 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. Remember, 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 humidity sensor into the WRL.
This may be done by utilizing the TWI_LOG program calibration routine. Index 6 is the voltage at
0% humidity that the sensor outputs. Index 7 represents the voltage that the sensor outputs at 73%
humidity. The humidity calibration numbers are found on the humidity/temperature sensor and
inside the instrument console. These calibration numbers are supplied to us by the manufacturer of
the sensor and are normally not changed. If it appears that re-calibration is necessary, try
increasing or decreasing index 7.
Rainfall
The WRL is compatible with most rain collectors on the market today. The rain inc flag is only
utilized to tell the WRL what type
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. Rain inc value tells the WRL how much rainfall to display for each count. Use the
TWI_LOG F5 calibration routine to change these settings.
THE PROPER SETTING FOR THE TEXAS WEATHER INSTRUMENTS RAIN COLLECTOR IS
"2" FOR THE COUNT AND ".01" FOR THE MEASUREMENT.
Texas Weather Instruments, Inc.
rain collector is installed. Actual measurement calibration is
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WRL Instruction Manual