Omron CQM1H-CLK21 - Manual (Page 202)

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Introduction Section 6-1
6-1-2 CMND (CVM1, CV-series, CS/CJ-series, and CQM1H-series PLCs
Only)
The CMND instruction can be executed in the user program in a CVM1, CV-
series, CS/CJ-series, or CQM1H-series PLC to perform operations such as
reading and writing memory data from and to other nodes, reading status
information, and changing the operating mode.
CS/CJ-series PLCs CMND sends “n” bytes of command data beginning with S (the beginning
send word for storing command data at the source node) to destination node
N. In return, “m” bytes of response data are stored at the source node begin-
ning with D (the beginning receive word for storing response data).
Note With the message service, there is no guarantee that a message to a destina-
tion node will reach its destination. It is always possible that the message may
be lost in transit due to noise or some other condition. When using the mes-
CMND(490)
S
D
C
"n" bytes
of com-
mand
data
"m" bytes
of
response
data
S
15 0
S: Source node beginning send word
D: Destination node beginning receive word
C: Source node first control data word
Source node Destination node N
(S –1)
+
n
2
D
(D –1)
+
m
2
Command
Response
Analysis
Execution
Destination node N
00 to 20 (Hex): 0 to 32 (or 00 to 3E (Hex): 0 to 62)
The same data can be broadcast to all nodes
on the network by setting the destination node address
to FF (Hex).
The range of node addresses will vary for networks
other than Controller Link Networks.
C+1
C+4 0 0
Number of retries
0 to F (Hex): 0 to 15 retries
0: Response required
1: Response not required
C
"n" bytes of command data
0000 to 07C6 (Hex): 0 to 1,990 words
0
"m" bytes of response data
0000 to 07C6 (Hex): 0 to 1,990 words
15 0
C+3
15 8 7 0
Destination unit address
00 (Hex):
PLC's CPU Unit
01 to 0F (Hex): Computer (user program)
10 to 1F (Hex): Unit nos. 0 to 15
E1 (Hex):
Inner Board
FE (Hex): Unit connected to network
15 11 8 7 3 0
15 10 8 7 3 0
Response monitor time
0000 (Hex): 2 s
0001 to FFFF (Hex): 0.1 to 6,553.5 s
(Unit: 0.1 s)
If the baud rate is slow, then setting a
small value may generate an error. The
standard is approximately 4 seconds at
1 Mbps or 8 seconds at 500 Kbps.
C+2 0 0
15 11 8 7 0
Destination network address
00 (Hex): Local network
01 to 7F (Hex): 1 to 127
C+5
15
… …
…
Communications port number: 0 to 7 (Hex)
(02 to 0F (Hex) are used
when using Controller
Link Support Boards for
PCI Bus only.)