Ptp Communication Protocol - idronaut Ocean Seven 304Plus Operator's Manual

SECTION SEVEN – PTP COMMUNICATION PROTOCOL
7.

PTP COMMUNICATION PROTOCOL

The OCEAN SEVEN 304Plus CTD is operated according to a series of rules and message formats
commonly indicated with the term "communication protocol". The OCEAN SEVEN 304Plus supports
a very simple communication protocol, with function selections (incoming data) and sensor readings
(outgoing data) assembled in "messages" whose generic structure is the following:
ID[ <param list>] <LF> or <CR>
"ID" is a two-character identification for the message; for example "PT" stands for single CTD real-
time acquisition. The message identification is optionally followed by a space and a list of parameters,
whose number and format strictly depend on the type of message.
Each incoming message must end with an <LF>, that is the ASCII character line-feed (0x0A
hexadecimal, 10 decimal). Vice versa, the Line Feed character on a PC keyboard can be obtained by
pressing the <CTRL-J> (press and hold the <CTRL> key, press and release the "J" key, release the
<CTRL> key). The CTD operates in "slave" mode, meaning that it does nothing but waits for user
commands to be received. When a complete message is received, its ID field is searched for in a
lookup table and, if a match is found, the system dispatches the received message to the appropriate
handler. The message handler is responsible for verifying each parameter and carrying out the desired
action; the action usually consists in assembling and sending back another message.
The document "OCEAN SEVEN 3xx Data Transmission Protocol" describes in detail the communication
protocol. It can be found in the download area of the IDRONAUT web site.
IDRONAUT – Brugherio (MB) OCEAN SEVEN 304Plus CTD
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12-2015