GE RX3i User Manual page 162

zero value to identify the failure. See the section "Status Data" later in this chapter for detailed CRS failure
codes.
Command 3003, Example 1
Read four Input Registers from Input Registers in the remote Modbus/TCP device. Store the registers at location
%R20. Return the COMMREQ Status word to %R10.
Dec
Word 1 00008 (0008)
Word 2 00000 (0000)
Word 3 00008 (0008)
Word 4 00009 (0009)
13
Word 5 00000 (0000)
Word 6 00000 (0000)
Word 7 03003 (0BBB)
Word 8 00006 (0006)
Word 9 00004 (0004)
Word 10 00008 (0008)
Word 11 00020 (0014)
Word 12 00200 (00C8)
Word 13 00004 (0004)
Word 14 00001 (0001)
(Word 7) Channel Command Number: Word 7 identifies the COMMREQ as a Read Data from Modbus/TCP
Device command block.
(Word 8) Channel Number: Word 8 identifies the channel number previously allocated for communication with
the remote Modbus/TCP server.
(Word 9) Modbus Function Code: Word 9 specifies Modbus Function Code 4, Read Input Registers.
GFK-2224Q
(Hex)
Length of Channel command Data Block
Always 0 (no-wait mode request)
Memory type of CRS word (%R)
CRS word address minus 1 (%R10)
Reserved
Reserved
Read from a Modbus/TCP Device
Channel number (6)
Modbus Function Code (Read Input Registers)
Local PLC Memory Type
Local PLC Starting Address
Address in the Remote Server
Number of Registers in the Remote Device
Unit Identifier
January 2017
Chapter 9. Modbus/TCP Client
149