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Texas Weather Instruments, Inc. 18 WRL Instruction Manual
The daily rainfall register is zeroed every day at midnight. The monthly rainfall register is
zeroed on the last day of each month at midnight. The term rainfall register is never zeroed
automatically, it must be manually zeroed through the calibration routine.
Report Flag
The report flag selects the format of the RS-232 output and may be changed via the the
print set mode or the TWICAL program calibration
SETTING MIN/MAX FORM FEED RAIN RATE
0 OFF OFF OFF
1 ON OFF OFF
2 OFF OFF OFF
3 ON ON OFF
4 OFF OFF ON
5 ON OFF ON
6 OFF OFF ON
7 ON ON ON
When rain rate is off, term rain is substituted.
Min/Max, when selected outputs at midnight the minimum and maximum value for the day.
The report function must be on in order for the output to occur. This function must also be
on if you want the minimum and maximum to be logged to memory.
Form Feed, when selected, sends a form-feed character at midnight, which is normally
desirable if a printer is directly hook up to the RS-232 interface.
Rainfall rate, when selected, outputs rainfall rate instead of term rain in the report function.
Lunar Tide Cycle
The lunar tide cycle function may be set to display the position of the moon in relation to its
revolution around the earth. The moon's position is the primary, although not the only, factor
in predicting high and low coastal tides. High tides are generally present when the moon is
overhead or when the moon is 180 degrees from overhead. Low tide is generally present
when the moon is in the 90 degree or the 270 degree position. This method of predicting
tide works well on the West and East coasts. On the Gulf coast, this method is not as
successful.
To set the tide clock, follow the directions in the time set function. The first item to be
entered is the tide cycle duration. The tide cycle duration may be set from 1 to 99 hours.
Twelve hours and fifty one minutes is the normal number for a tide clock. The second item
to be entered is the time of the high tide. This information is generally found in the
newspaper. If predicting the tide does not apply to your area, any cycle that lasts between
1 and 99 hours may be displayed. If you have the optional lighting sensor the lunar tide
display does not function as it is replaced with lightning data.
Clearing the Memories