GE RX3i

Chapter 9. Modbus/TCP Client
146 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual GFK-2224Q
Command 3000 Example
Establish a channel (Channel 5) to a remote Modbus/TCP device at IP address 10.0.0.1. Return the COMMREQ
Status word to %R10.
Dec (Hex)
Word 1 00008 (0008) Length of Channel command Data Block
Word 2 00000 (0000) Always 0 (no-wait mode request)
Word 3 00008 (0008) Memory type of CRS word (%R)
Word 4
13
00009 (0009) CRS word address minus 1 (%R10)
Word 5 00000 (0000) Reserved
Word 6 00000 (0000) Reserved
Word 7 03000 (0BB8) Open Modbus/TCP Client Connection
Word 8 00005 (0005) Channel number (5)
Word 9 00001 (0001) Remote Device Address Type
Word 10 00004 (0004) Length of Remote Device Address
Word 11 00010 (0010) Numeric value of 1
st
Octet
Word 12 00000 (0000) Numeric value of 2
nd
Octet
Word 13 00000 (0000) Numeric value of 3
rd
Octet
Word 14 00001 (0001) Numeric value of 4
th
Octet
(Word 7) Channel Command Number: Word 7 is the command id for an Open Modbus/TCP Client Connection
COMMREQ. If successful a TCP connection with the specified device is allocated.
(Word 8) Channel Number: Word 8 specifies the channel number to allocate for the Modbus/TCP Client
connection. Channels 1-32 can be used for Client communications.
(Word 9) Address Type: Word 9 specifies the type of IP Address specified for the remote device. A value of one
(1) is required in this word.
(Word 10) Length of IP Address: Word 10 specifies the length of the IP Address. A value of four (4) is required in
this word.
(Word 11) IP Address 1
st
Octet: Word 10 specifies the value of the first octet of the IP Address.
(Word 12) IP Address 2
nd
Octet: Word 11 specifies the value of the second octet of the IP Address.
(Word 13) IP Address 3rd Octet: Word 12 specifies the value of the third octet of the IP Address.
(Word 14) IP Address 4th Octet: Word 13 specifies the value of the fourth octet of the IP Address.