104
Overview of Explicit Message Communications
Section 6-1
6-1
Overview of Explicit Message Communications
6-1-1
Explicit Message Communications
Explicit message communications is a communications protocol for sending
commands from the master as explicit messages, and receiving explicit mes-
sages as responses from the nodes that receive the commands.
Explicit messages can be sent from the master to the DeviceNet Communica-
tions Unit to read and write the Temperature Controller variable area, send
operation commands, and read and write various other functions supported
by the DeviceNet Communications Unit.
Explicit message communications can be used to send and receive data that
is not allocated in the IN and OUT Areas due to word size restrictions, and
data that does not require the frequent refreshing used by the IN Area and
OUT Area.
Use either of the following two methods depending on the application.
Reading/Writing Temperature Controller Variable Area Data and Sending Operation Commands
Send Compoway/F communications commands to Temperature Controllers
by embedding them in explicit messages.
Reading/Writing Maintenance Information for the DeviceNet Communications Unit and Temperature
Controllers
Send explicit messages to the DeviceNet Communications Unit.
Note
This manual describes the contents of explicit messages that can be sent to
DeviceNet Communications Units. For details on the methods of sending
explicit messages, refer to the operation manual for the DeviceNet Unit being
used as the master.
DeviceNet Unit
CPU Unit
Master
(PLC)
IOWR or
CMND
instruction
CompoWay/F communications
command sent to Temperature
Controller (embedded in
explicit message)
Explicit message sent
to DeviceNet
Communications Unit
Slave
Slave
Temperature Controller
DeviceNet Communications Unit
Conversion
Unit
0
Unit
1
CompoWay/F
communications
command
Summary of Contents for EJ1 - 07-2008
Page 3: ...iv...
Page 19: ...xx...
Page 33: ...14 Initial Temperature Controller Settings Section 1 4...
Page 53: ...34 Wiring the Temperature Controllers Section 3 4...
Page 101: ...82 Ladder Programming Examples Section 4 6...
Page 143: ...124 Sending Explicit Messages Section 6 5...
Page 155: ...136 Message Communications Characteristics Section 7 2...
Page 163: ...144 Maintenance Section 8 2...
Page 189: ...170 Allocation Numbers for Configurators Manufactured by Other Companies Appendix B...
Page 197: ...178 Index...