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Introduction Section 6-1
sage service, it is advisable to prevent this situation from occurring by per-
forming resend processing at the node where instructions are issued. With
the SEND, RECV, and CMND instructions, resend processing is performed
automatically once the number of retries has been set, so be sure to specify a
number other than “0” for the number of retries.
CVM1 and CV-series PLCs CMND sends “n” bytes of command data beginning with S (the beginning
word for storing command data at the source node) to node N. In return, “m”
bytes of response data are stored at the source node beginning with D (the
beginning word for storing response data).
Note 1. When using CVM1 and CV-series PLCs manufactured prior to April 1996,
the local network address cannot be set to “00.” Set a number other than
CMND(194)
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
Communications port number: 0 to 7 (Hex)
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
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
…
…
…
(02 to 0F (Hex) are used
when using Controller Link
Support Boards for PCI
Bus only.)