Beginning And End Of Block Transmission; Device Id; Attribute Character (Attr); Block Check Character (Bcc) - sauter SW 1000 Instruction Manual

5.2.1 Beginning and end of block transmission

The command or response block contains a start character, end character and other
control characters described in the table below:
Name
<STX>
<ETX>
<CR>
<LF>

5.2.2 Device ID

Each command block contains an identifier (ID). It is used to differentiate several
sound level meters connected to a single network. After receiving a command block,
the sound level meter compares the command block ID with its own ID. The appro-
priate operation will be performed if both IDs are identical. Otherwise the command
will be ignored. The response block sent by the sound level meter also includes an ID
which defines the location from which the block was sent.
☆ Hint:
Make sure that the IDs of sound level meters connected to the same net-
work are different, otherwise the operation will be disturbed!
The ID is a single binary address byte. It ranges from 1 to 255, which corresponds to
the hexadecimal system values from 01H to FFH.
If the ID contained in a command block is 00H, it means a broadcast command. In
case of a broadcast command, the sound level meter executes the instruction re-
gardless of its own ID, without sending back the data.
Name
ID

5.2.3 Attribute character (ATTR)

The ATTR character determines the type of command or response.
Name
'C'
'A'
<ACK>
<NAK>

5.2.4 Block check character (BCC)

The BCC character in a block is calculated by the transmitter. Then the BCC value is
calculated by the receiver and compared to the BCC value in the transmitter block.
The received block is correct if both values are identical. The BCC value is calculated
from the bytes between <STX> and <ETX> characters using XOR operation. If the
SW-BA-e-1710
Value in hexadecimal sys-
tem
02H
03H
0DH
0AH
Value in hexadecimal sys-
tem
01H to FFH
00H
Value in hexadecimal sys-
tem
43H
41H
06H
15H
Meaning
Start of text
End of text
Carriage return
Line feed
Meaning
Device ID
Broadcast command
Meaning
Command block
Response block
Acknowledge
Negative acknowledge
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