6. DeviceNet COMMUNICATION
IMR01Y09-E3
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6.2 Communication Method
COM-JH has supported “Polling I/O communication” and “Explicit message communication” as a
communication method of DeviceNet.
6.2.1 Polling I/O communication
Polling I/O communication is the communication that master and slave always execute transmission
and reception of data. Used always when checking data items such as measured values, etc.
Set the following items before communication start.
•
Communication data items (setting data items and measured data items)
•
Number of communication controllers
•
Number of communication words
•
Controller address
•
Action mode
•
Automatic acquisition of controller address
Polling made once enables the following data items to be read or written via polling I/O communication.
Request: setting data items (OUT)
Response: measured data items (IN)
Setting state selection
Receive counter
RUN/STOP transfer
Alarm state
Selected set items
RUN/STOP state
Selected
measured
items
Outline of polling I/O communication
For data processed in actual communication, its decimal point is ignored. In addition,
data with a minus sign is expressed as 2’s complement data.
[Example 1]
For a set value of “120.0,” set “1200.”
[Example 2]
For a set value of “
−
1,” set “65535.”
(10000H
−
1 = FFFFH = 65535)
Slave
(COM-JH)
Master
(PLC)
Request
Setting state selection
RUN/STOP transfer
Selected set items
Response
DeviceNet
Receive counter
Alarm state
RUN/STOP state
Selected measured items
