iXBlue OCEANO RT2500S Series, Руководство пользователя

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OCEANO RT2500S/RT5000S Series – User Guide
In that kind of application, the CRF is configured as a tonal frequency pulse. When
receiving the acoustic order IIF, the ‘positioning’ pulse CRF is transmitted, followed by the
same tonal frequency.
This graph illustrates the acoustic transmission of pressure measurement:
Figure 22 – LBL transmitting cycle
CRF : Synchronization pulse (Tonal)
The 12 bits of the pressure measurement are totally ‘temporally’ transmitted.
K0 : Time resolution : 2,442 ms
T1 : Temporal encoding of the 12 MSB of the pressure measurement (T1 = k
×
2,442 ms)
T0 : Minimal value of the temporal encoding : 2 s
NB: The encoding unit used in pressure measurement transmission is still ‘2 dbars’.
We can notice that the measurement cycle is carried out after measurement encoding:
Every transmission is followed by a pressure measurement acquisition, and this value will
be transmitted at next interrogation. This implies a ‘shift back’ between acoustic
interrogations and pressure measurements which are transmitted.
VII.2.3 T
RANSMISSION OF THE
P
RESSURE
M
EASUREMENT ON
S
ERIAL
L
INK
The transmission of pressure measurement on serial link is enabled by selecting the link
in MMI BALI.
Serial port:
•
Non-insulated RS 232 by default (RS422 as option)
•
Asynchronous series, 4800 bauds,
•
1 start bit, 8 data bit without parity, 1 Stop bit.
The message is transmitted as a NMEA 0183 packet.
$PMEVL,XP,MEA,C,VVVVV*cc<CR><LF>
XP
MEA
C
VVVVV
*cc
is the transponder ID (from 001 up o 128)
is a mnemonic
is the analog channel, C = 8
is the Pressure value
VVVVV = 0 to 65535 dBars (integer)
or VVVV.V = 0.0 to 9999.9 dbars (float)
is the checksum
LBL
MU–RT8x1–AN–001 Ed. M – September 2013 31