Chapter 4 _________________________________________________________________ Operation
VAISALA ________________________________________________________________________ 91
MITRAS Emulation
For compatibility in the system level, the FS11P sensor also supports the
message format, frames, and polling format of Vaisala MITRAS
Transmissometer. The MITRAS polling format is accepted only when
the MITRAS message emulation is selected.
The MITRAS polling format is as follows:
P<Space><ID>
.
MITRAS Single Baseline
The MITRAS Single Baseline emulation mode is selected with the
command SET MESSAGE TYPE MITRAS. The emulated Vaisala
MITRAS Transmissometer message is presented below:
ID 1 V 4550 B ///// S0101
----------------------------------
¦ ¦ ¦ ¦ ¦ ¦ ¦¦ ¦___receiver 1 status
¦ ¦ ¦ ¦ ¦ ¦ ¦¦___transmitter status
¦ ¦ ¦ ¦ ¦ ¦ ¦____S, status heading
¦ ¦ ¦ ¦ ¦ background luminance value
¦ ¦ ¦ ¦ ¦___B,background luminance heading
¦ ¦ ¦ ¦_____ visibility m, 1 min average
¦ ¦ ¦________V, visibility heading
¦ ¦________unit ID (one character only)
¦_________ID, start indicator
The total amount of characters in the message is 33. The transmission
times are: 1.3 s at 300 bps (10-bit char), 0.17 s at 2400 bps, 0.04 s at
9600 bps.
The binary status is in hexadecimal notation. The status bits emulate the
MITRAS status as follows.
Transmitter status correspondence between MITRAS and FS11P:
BL sensor status (ON/OFF)