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May
2015
WorkHorse H-ADCP Operation Manual
Page 208
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Variable Leader data refers to the dynamic H-ADCP data (from clocks/sensors) that change with each
ping. The H-ADCP always sends Variable Leader data as output data (LSBs first).
Table 37:
Variable Leader Data Format
Hex Digit
Binary Byte
Field
Description
1-4
1,2
VID / Variable Leader
ID
Stores the Variable Leader identification word (80 00h).
5-8
3,4
Ens / Ensemble Num-
ber
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 se-
quence:
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 H-ADCP’s real-time clock (RTC) that the cur-
rent data ensemble began. The TS-command (Set Real-Time Clock) initially sets the
clock. The H-ADCP 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 H-ADCP’s Built-in Test function. A zero code
indicates a successful BIT result.
BYTE 13 BYTE 14
(BYTE 14 RESERVED FOR FUTURE USE)
1xxxxxxx xxxxxxxx = RESERVED
x1xxxxxx xxxxxxxx = RESERVED
xx1xxxxx xxxxxxxx = RESERVED
xxx1xxxx xxxxxxxx = DEMOD 1 ERROR
xxxx1xxx xxxxxxxx = DEMOD 0 ERROR
xxxxx1xx xxxxxxxx = RESERVED
xxxxxx1x xxxxxxxx = TIMING CARD ERROR
xxxxxxx1 xxxxxxxx = RESERVED
29-32
15,16
EC / Speed of Sound
Contains either manual or calculated speed of sound information (EC-command).
Scaling: LSD = 1 meter per second; Range = 1400 to 1600 m/s
33-36
17,18
ED / Depth of Trans-
ducer
Contains the depth of the transducer below the water surface (ED-command). This
value may be a manual setting or a reading from a depth sensor.
Scaling: LSD = 1 decimeter; Range = 1 to 9999 decimeters
37-40
19,20
EH / Heading
Contains the H-ADCP heading angle (EH-command). This value may be a manual
setting or a reading from a heading sensor.
Scaling: LSD = 0.01 degree; Range = 000.00 to 359.99 degrees
41-44
21,22
EP / Pitch (Tilt 1)
Contains the H-ADCP pitch angle (EP-command). This value may be a manual setting
or a reading from a tilt sensor. Positive values mean that Beam #3 is spatially higher
than Beam #4.
Scaling: LSD = 0.01 degree; Range = -20.00 to +20.00 degrees
45-48
23,24
ER / Roll (Tilt 2)
Contains the H-ADCP roll angle (ER-command). This value may be a manual setting
or a reading from a tilt sensor. For up-facing H-ADCPs, positive values mean that
Beam #2 is spatially higher than Beam #1. For down-facing H-ADCPs, positive values
mean that Beam #1 is spatially higher than Beam #2.
Scaling: LSD = 0.01 degree; Range = -20.00 to +20.00 degrees