LSIS LSLV-S100 - Page 252

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RS-485 Communication Features
7.3.1.1 Detailed Read Protocol
Read Request: Reads successive n words from address XXXX.
ENQ
Station ID
CMD
Address
Number of
Addresses
SUM
EOT
05h
‘01’-’FA’
‘R’
‘XXXX‘
‘1’-‘8 ’ = n
‘XX’
04h
1 byte
2 bytes
1 byte
4 bytes
1 byte
2 bytes
1 byte
Total bytes=12. Characters are displayed inside single quotation marks(‘).
Read Normal Response
ACK
Station ID
CMD
Data
SUM
EOT
06h
‘01’-‘FA’
‘R’
‘XXXX’
‘XX’
04h
1 byte
2 bytes
1 byte
n x 4 bytes
2 bytes
1 byte
Total bytes= (7 x n x 4): a maximum of 39
Read Error Response
NAK
Station ID
CMD
Error code
SUM
EOT
15h
‘01’-‘FA’
‘R’
‘**’
‘XX’
04h
1 byte
2 bytes
1 byte
2 bytes
2 bytes
1 byte
Total bytes=9
7.3.1.2 Detailed Write Protocol
Write Request: Writes successive n words to address XXXX.
ENQ
Station ID
CMD
Address
Number of
Addresses
Data
SUM
EOT
05h
‘01’-‘FA’
‘W’
‘XXXX’
‘1’-‘8 ’ = n
‘XXXX…’
‘XX’
04h
1 byte
2 bytes
1 byte
4 bytes
1 byte
n x 4 bytes
2 bytes
1 byte
Total bytes= (12 + n x 4): a maximum of 44
Write Normal Response
ACK
Station ID
CMD
Data
SUM
EOT
06h
‘01’-‘FA’
‘W’
‘XXXX…’
‘XX’
04h
1 byte
2 bytes
1 byte
n x 4 bytes
2 bytes
1 byte
Total bytes= (7 + n x 4): a maximum of 39