October 2017
RiverPro and RioPro ADCP Guide
Page 150
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
The RiverPro/RioPro packs velocity data for each depth cell of each beam into a two-byte, two’s-comple-
ment integer [-32768, 32767] with the LSB sent first. The RiverPro/RioPro scales velocity data in millime-
ters per second (mm/s). A value of –32768 (8000h) indicates bad velocity values.
All velocities are relative based on a stationary instrument. To obtain absolute velocities, algebraically re-
move the velocity of the instrument. For example,
RELATIVE WATER CURRENT VELOCITY: EAST 650 mm/s
INSTRUMENT VELOCITY : (-) EAST 600 mm/s
ABSOLUTE WATER VELOCITY : EAST 50 mm/s
The setting of the EX-command (Coordinate Transformation) determines how the RiverPro/RioPro refer-
ences the velocity data as shown below.
EX-CMD
COORD SYS
VEL 1
VEL 2
VEL 3
VEL 4
EX00xxx
BEAM
TO BEAM 1
TO BEAM 2
TO BEAM 3
TO BEAM 4
EX01xxx
INSTRUMENT
Bm1-Bm2 axis
Bm4-Bm3 axis
TO XDUCER
ERR VEL
EX10xxx
SHIP
PRT-STBD
AFT-FWD
TO SURFACE
ERR VEL
EX11xxx
EARTH
TO EAST
TO NORTH
TO SURFACE
ERR VEL
Positive values indicate water movement toward the RiverPro/RioPro
Table 21:
Velocity Data Format
Hex Digit
Binary Byte
Field
Description
1-4
1,2
Velocity ID
Stores the velocity data identification word (00 01h).
5-8
3,4
Depth Cell 1, Veloc-
ity 1
Stores velocity data for depth cell #1, velocity 1. See above.
9-12
5,6
Depth Cell 1, Veloc-
ity 2
Stores velocity data for depth cell #1, velocity 2. See above.
13-16
7,8
Depth Cell 1, Veloc-
ity 3
Stores velocity data for depth cell #1, velocity 3. See above.
17-20
9,10
Depth Cell 1, Veloc-
ity 4
Stores velocity data for depth cell #1, velocity 4. See above.
21-2052
11-1026
Cells 2 – 128 (if
used)
These fields store the velocity data for depth cells 2 through 128 (depending on the
setting of the WN-command). These fields follow the same format as listed above for
depth cell 1.
