Channel Master CM-5020 Specifications download pdf (Page 135)

Channel Master Operation Manual

P/N 95B-6001-00 (February 2006) page 127

14 How to Decode a Channel Master Ensemble

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

14.1 Rules for the Channel Master Data Format PD0

a. 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 33: 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

0x4000 Surface Track Status

0x4001 Surface Track Commands

0x4002 Surface Track Amplitude

b. 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 “c”.

c. 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 con-

tains information on ensemble number, time, heading, pitch, roll, tem-

perature, pressure, etc. The format for the bytes 1-65 are now specified

by changes added in support to the Channel Master ADCP. If additional

sensor data is to be added to the variable leader data then it must be

added to the end of the data string (bytes 66-x as an example).

d. 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.

e. The header data will include the number of data types in the files and

the offset to each ID number for each data type.

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Channel Master CM-5020 Specifications Page 135