User's Guide ______________________________________________________________________
162 _________________________________________________________________ M210667EN-C
polled or it can send predefined messages automatically at selected
intervals. There are eight message formats to select from. As a default,
LT31 adds frame strings to all polled and LT31-specific, automatic
messages. The polling request can ask for the automatic (default) or some
other message (with a message number).
When used as a part of an existing RVR system, LT31 can emulate the
messages of Vaisala MITRAS Transmissometer, FD12 Visibility Meter,
and Impulsphysik SKOPOGRAPH II Flamingo. To find out which
message types can be emulated, see sections Message 5 and 6 - FD12
Emulation on page 177, Message 7 - MITRAS Emulation on page 188,
and Message 8 - Flamingo Emulation on page 180. LT31 also accepts
MITRAS, FD12, and Flamingo type of polling by the RVR computer
when the emulation is on.
MESSAGE Command
The
MESSAGE
command is used for displaying messages. The
command format is the following:
MESSAGE
Message_number
If the message number is not specified, LT31 displays a default message.
The default message is the message that has been selected for automatic
or polled mode with the
SET MESSAGE TYPE
command.
NOTE
When displaying a message with the
MESSAGE
command, the
message frames are not displayed.
All message frames end with
-*
which represent the carriage return and
line feed characters. These characters are also used as line separators in
multi-line messages.
The contents of the messages are described in the next sections.
Message 1 - LT31 Standard Message
Message 1 is of fixed length where both meteorological optical range
(MOR) and background luminance values (in case optional LM21 is
installed) are shown. The message format is as follows:
!
LT1
"
VIS 10000.0 AL 00000000000000000000 BL 01000 AL 0
#
CSUM
$-*