8 Message Communications
8-4
NJ-series CPU Unit Built-in EtherNet/IP Port User’s Manual (W506)
CIP message communications include the following processes. If CIP class 3 connections are used, the
open and close processes are required before and after the data is sent and received.
*1 There can be up to 32 handles at the same time from opening connections. Even if a connection is broken for a timeout,
the handle is not released. Execute the CIPClose instruction.
*2 Addresses in memory for CJ-series Units (e.g., D0000) cannot be specified directly. To access memory for CJ-series
Units, access a variable with an AT specification.
CIPOpen
Open CIP Class
3 Connection
This instruction opens a CIP class 3 connection with the specified
remote node.
CIP class 3 con-
nection mes-
sage
CIPRead
Read Variable
Class 3 Explicit
Reads the value of a variable with a Network Publish attribute from
the specified remote Controller on the CIP network and stores the
value in a variable at the local Controller.
CIPWrite
Write Variable
Class 3 Explicit
Writes the value of a variable at the local controller to a variable
with a Network Publish attribute at the specified remote Controller
on the CIP network.
CIPSend
Send Explicit
Message Class
3
Sends a specified class-3 CIP command to the specified remote
Controller on the CIP network.
Refer to 8-2-9 Response Codes and 8-3 CIP Objects Sent to the
Built-in EtherNet/IP Port for information on the service codes and
response codes that are used with the NJ-series CPU Units.
CIPClose
Close CIP Class
3 Connection
This instruction closes the CIP class 3 connection that is specified
by the handle.
8-2-3 Using CIP Communications Instructions
Process Description Instruction
Open process
*1
(only for CIP
class 3 connec-
tions)
Execute this process before you use a CIP message. Open pro-
cessing is continued until a connection is established.
CIPOpen
Sending and
receiving vari-
able data
*2
This process is used to read and write data for specified variables
with the Network Publish attributes.
CIPUCMMRead
CIPUCMMWrite
CIPRead
CIPWrite
Sending CIP
commands
You can set the required CIP command. CIPUCMMSend
CIPSend
Close process
(only for CIP
class 3 connec-
tions)
This process closes the connection. CIPClose
Instruction Name Description
Communica-
tions method
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