GE GFK-1541B manual Command 3000 Example, Dec Hex

4

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	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 1st Octet
Word 12	00000	(0000)	Numeric value of 2nd Octet
Word 13	00000	(0000)	Numeric value of 3rd Octet
Word 14	00001	(0001)	Numeric value of 4th Octet

*Word 4 (CRS word address) is the only zero-based address in the Command Block. Only this value requires subtracting 1 from the intended address.

(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 1-16 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 1st Octet: Word 10 specifies the value of the first octet of the IP Address.

(Word 12) IP Address 2nd 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.

GFK-1541B Chapter 4 Programming Modbus/TCP Channel Commands 4-9