2014-
02
68
Commands
Single write words (SW)
Command:
Response:
The R/W head makes one attempt to write <WordNum> 32-bit words from the
address<WordAddr>.
Within the reply from the read/write head, <WordNum> is always 0, because the answer does
not contain any user data.
Byte
Type
Bit no.
7
6
5
4
3
2
1
0
Byte 0*
Telegram length, high byte
<TelegramLenH>
Byte 1*
Telegram length, low byte
<TelegramLenL>
Byte 2
Command code (40h)
0
1
0
0
0
0
0
0
Byte 3
Word number/Channel/Toggle bit
<WordNum>
<Channel>
<T>
Byte 4
Word address
<WordAddr> (high byte)
Byte 5
Word address
<WordAddr> (low byte)
Byte 6
Data 00h ... FFh
<Data>
...
Data 00h ... FFh
<Data>
Byte N
1)
Data 00h ... FFh
<Data>
Byte
Type
Bit no.
7
6
5
4
3
2
1
0
Byte 0*
Telegram length, high byte
0
0
0
0
0
0
0
0
Byte 1*
Telegram length, low byte
0
0
0
0
0
1
1
0
Byte 2
Command code (40h)
0
1
0
0
0
0
0
0
Byte 3
Word number/Channel/Toggle bit
0
<Channel>
<T>
Byte 4
Status
<Status>
Byte 5
Reply counter
<ReplyCounter>
Table 7.17
* this byte is only used with the TCP/IP and MODBUS TCP/IP protocol.
1) N = 4 x <WordNum> + 5; Ethernet/IP: N = 4 x <WordNum> + 3
