Spectracom 8194B, Инструкция по эксплуатации

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Spectracom Corporation 8194B, 8195B, 8197B
GPS Ageless Master Oscillator Instruction Manual 4-27
4.4 RS-485 Command Structure
The commands described here must conform to a specific command protocol. The
protocol is shown in Table 4-5.
FIELD SIZE DESCRIPTION
Start Word 2 Bytes Unique characters <#> <$> used to
synchronize with data stream
Source Address 1 Byte 0-31= unit address
32-254= reserved
255= broadcast
Destination
Address 1 Byte 0-31= unit address
32-254=reserved
255= broadcast
Message Length 2 Bytes Variable length from 1 to 502 bytes
Message 1 to 502 Bytes 4 character commands plus parameters
Check Word 2 Bytes Running sum including all bytes after the
start word through the last message byte.
Stop Word 2 Bytes Unique characters (<cr><lf>) used to
synchronize with data stream
Table 4-5 RS-485 Command Protocol
All inputs via the RS-485 port must follow this format, or they will be ignored. The
descriptions that follow are for the Message field of the commands. When the first
character of a command is ‘w’ this indicates the controller is writing information to the
unit. If the first character is ‘r’ the controller is reading information. The RS-485 Com
port operates at 9600 baud, character structure is 1 start, 8 data, 1 stop, and no parity.