Van Essen CTD-Diver DI28 Series, Product Manual

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5 Appendix II CTD-Diver Communication Protocol
Introduction
The CTD-Diver supports a set of commands that allows the user to communicate with the Diver
through other software than Diver-Office. The following commands are available:
• reading measured/stored data
• read date/time
• read serial number
•
read monitoring point name
•
real-time pressure, temperature and conductivity value including time stamp
• read sample mode (record method and interval)
• read product ID, name, and firmware version
• read remaining battery capacity
•
read status: started, stopped, future start, free memory
Serial Port Settings
Bitrate: 9600
Parity: None
Databits: 8
Stopbits: 1
Frame Format
The frame format for a command/response is:
STX (1 byte) Length (1 byte) OC (2 bytes) Payload (n bytes) CC (1 byte)
field size description remarks
STX 1 byte Start of text, value is 0x02 Used to identify start of command
Length 1 byte Length of frame Number of bytes in frame including STX
and Checksum
OC 2 bytes OpCode Identifies the OpCode type
Payload n bytes Data field (n bytes) Data in command or response
CC 1 byte Checksum Ones complement of the low byte of
the sum of all bytes excluding CC
Time-out:
• All bytes must be sent with a maximum delay of 30 ms between the bytes.
•
When the delay exceeds 30 ms, a communication error response will be sent.