Blueprint Subsea seatrac X100 Series, Руководство пользователя

Страница: 45 / 140

SeaTrac Serial Command Interface Reference
Page 45
6.4. Structures
Structures (sometimes called Records or Structs) are declarations defining complex data types
of physically grouped variables placed under one name in a block of memory.
For the scope of this document, the members (or fields) of Structures should be assumed to be
defined sequentially in memory, with no additional packing bytes added.
6.4.1. ACOMSG_T (Acoustic Message)
The Acoustic Message structure described the contents of packets that are transmitted
between beacons acoustically, and form the basis for all information transfer in higher level
protocols.
Parameter Type Description
MSG_DEST_ID BID_E Identifier for the beacon the message is or was the
recipient of the message.
MSG_SRC_ID BID_E Identifier for the beacon that generated or sent the
message.
MSG_TYPE AMSGTYPE_E Value that indicates the type of message being sent
MSG_DEPTH UINT16 Value that is only valid when MSG_TYPE is
MSG_RESPX (an extended USBL response), and
contains the depth sensor reading from the remote
beacon. The depth is encoded 0.5m steps, and so
should be divided by 2 to obtain a depth in metres.
MSG_PAYLOAD_ID APAYLOAD_E Value that indicates the type of payload the
message contains.
MSG_PAYLOAD_LEN UINT8 Values specifying how many bytes in the payload
array are valid and in use. Valid values are from 0
(for no payload) to 31.
MSG_PAYLOAD UINT8[31] Array of 31 bytes that contains the payload of the
acoustic message.
Only the number of bytes specified in the
PAYLOAD_LEN parameter are valid, while the
contents of the other locations are undefined.
The exact function and definition of the PAYLOAD
bytes depends on the type of payload specified in
the PAYLOAD_ID parameter.