How To Decode An H-Adcp Ensemble; Rules For The Broadband Data Format Pd0; Table 51: Common Data Format Ids - Teledyne WORKHORSE Operation Manual

WorkHorse H-ADCP Operation Manual

How to Decode an H-ADCP Ensemble

Use the following information to help you write your own software.

Rules for the BroadBand Data Format PD0

1. All data types (i.e. fixed leader, variable leader, velocity, echo intensity, correlation, percent good,
etc.) will be given a specific and unique ID number. The table below shows some of the most
common IDs.
Table 51: Common Data Format IDs
ID Description
0x7F7F Header
0x0000 Fixed Leader
0x0080 Variable Leader
0x0100 Velocity Profile Data
0x0200 Correlation Profile Data
0x0300 Echo Intensity Profile Data
0x0400 Percent Good Profile Data
0x0500 Status Profile Data
0x0600 Bottom Track Data
0x0800 MicroCAT Data
2. Once a data type has been given an ID number and the format of that data has been published we
consider the format for each field has being fixed. Fixed refers to units used for a given field, the
number of bytes in a given field, and the order in which the fields appear within the data type.
Fixed does not refer to the total number of bytes in the data type - see Rule 3.
3. Data may be added to an existing data type only by adding the bytes to the end of the data format.
As an example, the variable leader data contains information on ensemble number, time, heading,
pitch, roll, temperature, pressure, etc. The format for the bytes 1-53 are now specified by changes
added in support to the H-ADCP. If additional sensor data is to be added to the variable leader da-
ta, than it must be added to the end of the data string (bytes 54-x as an example).
Note that new firmware versions may cause a change in the number of bytes and this implies
that if byte-counting, requires altering your code at every change. This is not the case when
using the data type IDs and offsets to navigate through the data. New variables are added at the
end of a data type before the checksum. The offsets will dynamically change to reflect the
change, allowing you to get to the same desired data every time.
4. The order of data types in an ensemble is not fixed. That is there is no guarantee that velocity data
will always be output before correlation data.
5. The header data will include the number of data types in the files and the offset to each ID num-
ber for each data type.
6. The total number of the bytes in an ensemble minus the 2-byte checksum will be included in the
header.
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
May 2015
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