Specifications
Channel Master Operation Manual
page 90 RD Instruments
Variable Leader data refers to the dynamic Channel Master data (from
clocks/sensors) that change with each ping. The Channel Master always
sends Variable Leader data as output data (LSBs first).
Table 19: Variable Leader Data Format
Hex Digit Binary
Byte
Field Description
1-4 1,2 VID / Variable
Leader ID
Stores the Variable Leader identification word 0080 (80 00h).
LSB is sent first.
5-8 3,4 Ens / Ensemble
Number
This field contains the sequential number of the ensemble to
which the data in the output buffer apply.
Scaling: LSD = 1 ensemble; Range = 1 to 65,535 ensembles
NOTE: The first ensemble collected is #1. At “rollover,” we
have the following sequence:
1 = ENSEMBLE NUMBER 1
↓
65535 = ENSEMBLE NUMBER 65,535 | ENSEMBLE
0 = ENSEMBLE NUMBER 65,536 | #MSB FIELD
1 = ENSEMBLE
NUMBER 65,537 | (BYTE 12)
INCR.
9,10
11,12
13,14
15,16
17,18
19,22
21,22
5
6
7
8
9
10
11
RTC Year
RTC Month
RTC Day
RTC Hour
RTC Minute
RTC Second
RTC Hundredths
These fields contain the time from the Channel Master’s real-
time clock (RTC) that the current data ensemble began. The
TS-command (Set Real-Time Clock) initially sets the clock.
The Channel Master does
account for leap years.
23-24 12 Ensemble #
MSB
This field increments each time the Ensemble Number field
(bytes 3,4) “rolls over.” This allows ensembles up to
16,777,215. See Ensemble Number field above.
25-28 13,14 BIT / BIT Result This field contains the results of the Channel Master’s Built-in
Test function. A zero code indicates a successful BIT result.
MSB BYTE 14 LSB BYTE 13
76543210 76543210
xxxxxxxx xxxxxxx1 =
transmitter shutdown
xxxxxxxx xxxxxx1x =
transmitter over current
xxxxxxxx xxxxx1xx = transmitter under current
xxxxxxxx xxxx1xxx =
transmitter under voltage
xxxxxxxx xxx1xxxx =
FIFO interrupt missed
xxxxxxxx xx1xxxxx =
FIFO ISR Re-entry
xxxxxxx1 xxxxxxxx =
Sensor module failure
xxxxxx1x xxxxxxxx =
Watchdog disabled
29-32 15,16 EC / Speed of
Sound
Contains either manual or calculated speed of sound informa-
tion (EC-command).
Scaling: LSD = 1 meter per second; Range = 1400 to 1600
m/s
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