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Advanced Microwave
Technologies
DVANTECH
8. APPENDIX A: RS-485 SERIAL COMMUNICATION PROTOCOL
The protocol described in this Section is used for the interconnection between the SSPB Up-
Converter unit and the user's monitoring and control system. The protocol supports the 4-wire
RS-485 inte
rface using the communication set-up
8.1 FRAME ST
RUCTURE
Each f
rame begins with the same starting byte: 0x55.
After the starting byte, 7 bytes are following.
The first byt
e in the master-to-slave direction is t
0x07; the address 0x00 is the broadcast address - it must be used only for commands).
The first byte
in the slave-to-master direction co
by 4 (e.g. the unit with the address 0x05 will return address 0x50).
The second byte
in the master-to-slave direct
The third,
forth and fifth bytes in the master-to-slav
expansion of th
e command. The third byte is th
significant (LS) byte, and the fifth byte is the value after the decima
The second to the sixth bytes in the slave-to-master direction carry data or status from the slave
unit.
The seventh byte in both the master-to-slave and the slave-to-master directions carry the check-
sum, calculated as algebraic sum of bytes 1-6.
All not used (N/U) bytes are always set to 0xAA.
The format for gain, level, current consumption and temperature is a 2-bytes hexadecimal value
in 0.1 dB, 0.1 dBm, 0.1 Amp or 0.1 degree (signed integer).
If the unit does not recognize the command, or if the checksum is not correct, the response will
be always "condition status".
The commands marked N/A are not available for these units.
9600.N.8.1.
he address of the c
ntains the address o
ion is a command or a
e direction carry
e most significant (MS) byte, the fourth is the less
SSPBM-K125-BTE
orrespondent unit
(0x01 to
f the unit, shifted
to the left
data request.
the value of para
meter or an
l point.
Page 36
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