6. DeviceNet COMMUNICATION
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6.2.2 Explicit message communication
Explicit message communication uses an Explicit message defined with DeviceNet, and be
communication to execute transmission and reception of data between nodes when it is necessary.
Explicit message communication is executed like the following, when COM-JH (slave) is connected to
a master instrument with DeviceNet.
In Explicit message communication, not only data relating to the COM-JH but also all of the
attributes (data) described in
APPENDIX A. DEVICE PROFILES (P. 94)
are subject to
being sent or received.
When read data
If the node address (MAC ID), service code (0EH: Get_Attribute_Single), object class ID, instance ID
and attribute ID are sent from the master, the node address (MAC ID) thus sent and service code (0EH
+ 80H *) as well as the data requested are sent from the slave.
* 80H represents a response message.
Service code 14H of “Error response” has shown that it is error response.
For Error code of “Error response”, see DeviceNet specifications.
[Normal response]
Request
Master
(PLC)
Slave
(COM-JH)
Node address (MAC ID)
Service code (0EH)
Object class ID
Instance ID
Attribute ID
Response
Node address (MAC ID)
Service code (0EH
+
80H)
Request data
DeviceNet
[Error response]
Request
Master
(PLC)
Slave
(COM-JH)
Node address (MAC ID)
Service code (0EH)
Object class ID
Instance ID
Attribute ID
Response
Node address (MAC ID)
Service code (14H
+
80H)
Error code
DeviceNet