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The pin out on the RS-232interface is as follows:
.DE 9 Plug Header
Pin 1 Pin 1 . . .
Pin 2 Pin 3 . . . Receive Data
Pin 3 Pin 5 . . . Transmit Data
Pin 4 Pin 7 . . . . Data Set Ready
Pin 5 Pin 9 . . . Signal Ground
Pin 6 Pin 2 . . . Data Terminal Ready (must be true to send data)
Pin 7 Pin 4 . . . Clear to Send
Pin 8 Pin 6 . . . Request Send
Pin 9 Pin 8 . . .
Modem Installation
A modem may be used with the WR-25 for remote operations. A modem adapter which is available
from TWI must be used to properly connect the weather station to a modem. For auto answering, an
auto-answering modem with non-volatile memory must be used. The WR-25 does not send AT
control signals, so in order for the modem to properly answer, the modem must be told
(programmed with a computer) to answer on whichever ring the user desires. (Modems
pre-programmed in non-volatile memory are available from Texas Weather Instruments.)
Typical Output
Temperature Daily Monthly Rainfall
Time Date Direction Speed Aux Indoor Outdoor Humidity Pressure Rain Rain Rate
15:00 07/24/90 SE 03MPH 070F 069F 082F 090% 30.04S 00.01"D 01.20"M 00.00"R
15:15 07/24/90 SSE 04MPH 052F 069F 078F 099% 30.04S 00.19"D 01.38"M 00.72"R
15:30 07/24/90 SE 02MPH 065F 068F 072F 089% 30.04S 00.19"D 01.38"M 00.00"R
MIN 07/24/90 SW 00MPH 070F 067F 067F 054% 30.00" 00.19"D 01.38"M 00.00"R
MAX 07/24/90 SSE 25MPH 052F 071F 092F 099% 30.06" 00.19"D 01.38"M 00.72"R
Computer Interface
The WR-25 may be plugged directly into computers equipped with RS-232 interfaces. Data may be
captured to disk by using a communication program (i.e., Crosstalk or Procomm for the IBM-PC) or
the TWI_LOG program. The WR-25 sends data in a serial format at 300 to 19.2 baud rate, 8 data
bits, no parity and one stop bit.
Note: The WR-25 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
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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
WR-25 Instruction Manual
Texas Weather Instruments, Inc. WR-25 Instruction Manual