Sample Programming For Cip Connection (Class 3) Message Communications - Omron CJ1W-EIP21 Operation Manuals

8-2-7 Sample Programming for CIP Connection (Class 3) Message
Communications
This sample uses CIP class 3 messages to write a variable, read a variable, and send a message. The
Controllers are connected to an EtherNet/IP network. The IP address of the remote node is
192.168.250.2. The following procedure is used.
1
The CIPOpen instruction is used to open a class 3 connection. The timeout time is 2 s.
2
The CIPWrite instruction is used to write the value of a variable at a remote node. The variable
name at the remote node is WritingDat and the contents of the WriteDat is written to it. Writing-
Dat must be defined as a global variable at the remote node and the Network Publish attribute
must be set.
3
The CIPRead instruction is used to read the value of a variable at a remote node. The value of
the variable OriginalDat at the other node is read and the read value is stored in the ReadDat
variable. OriginalDat must be defined as a global variable at the remote node and the Network
Publish attribute must be set.
4
The CIPSend instruction is used to send an explicit message to a remote node. The contents of
the message is to read identity information (product name). The class ID, instance ID, attribute
ID, and service code are as follows: The response data is stored in the RespDat variable.
Class ID
Instance ID
Attribute ID
Service code
5
The CIPClose instruction is used to close the class 3 connection.
EtherNet/IP Unit
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
Item Value
1
1
7
16#0E
Unit number: 0
Value of variable written.
WriteDat
Value of variable read.
ReadDat
Message sent to read identity
information (product name).
RespDat
Response
8 Message Communications
IP address: 192.168.250.2
Unit number: 1
EtherNet/IP Unit
Variable name: WritingDat
Global variable
Network Publish attribute
Variable name: OriginalDat
Global variable
Network Publish attribute
8
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