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GFK-1084B Chapter 3 Programming Communications Requests
Example 2 Command Block–Example using a Network Address Name
This example is the same as example 1 except that the Network Address name of the
Remote PLC (“PLC_1aa”) is used instead of its IP address. For more information on
Network Address names, see Appendix F.
Establish a channel (channel 5) to a remote PLC at IP address 3.0.0.1. Return the
COMMREQ Status word to %R10. Read remote PLC registers %R50-%R57 to local PLC
registers %R100-%R107. Repeat the read 10 times once every 7 seconds with a timeout
of 500 ms for each read.
Dec (Hex)
Word 1 00045 (002d) Length of Channel Command Data Block (45 - 53 words)
Word 2 00000 (0000) Always 0 (no-wait mode request)
Word 3 00008 (0008) Memory type of CRS word (%R)
Word 4 00009 (0009) CRS word address minus 1 (%R10)*
Word 5 00000 (0000) Reserved
Word 6 00000 (0000) Reserved
Word 7 02003 (07d3) Establish Read Channel Command number
Word 8 00005 (0005) Channel number (5)
Word 9 00010 (000A) Number of read repetitions (read 10 times)
Word 10 00003 (0003) Time unit for read period (3=seconds)
Word 11 00007 (0007) Number of time units for read period (every 7 seconds)
Word 12 00050 (0032) Timeout for each read (500 ms)
Word 13 00008 (0008) Local PLC - Memory type at which to store data (%R)
Word 14 00100 (0064) Local PLC - Starting address at which to store data (%R100)
Word 15 00008 (0008) Remote PLC - Memory type from which to read data (%R)
Word 16 00050 (0032) Remote PLC - Starting address from which to read data (%R50)
Word 17 00008 (0008) Remote PLC - Number of memory units (8 registers)
Word 18 00003 (0003) Remote PLC - Network address type (3=Symbolic Name)
Word 19 00032 (0020) Remote PLC - Network address length in words (32)
Word 20 19536 (4c50) Remote PLC - Network address name, char 1-2 (“PL”)
Word 21 16451 (4043) Remote PLC - Network address name, char 3-4 (“C_”)
Word 22 24881 (6131) Remote PLC - Network address name, char 5-6 (“1a”)
Word 23 00097 (0061) Remote PLC - Network address name, char 7-8 (“a ”)
Word 24 00000 (0000) Remote PLC - Network address name, char 9-10
Word 25 00000 (0000) Remote PLC - Network address name, char 11-12
Word 26 00000 (0000) Remote PLC - Network address name, char 13-14
Word 27 00000 (0000) Remote PLC - Network address name, char 15-16
Word 28 00000 (0000) Remote PLC - Network address name, char 17-18
Word 29 00000 (0000) Remote PLC - Network address name, char 19-20
Word 30 00000 (0000) Remote PLC - Network address name, char 21-22
Word 31 00000 (0000) Remote PLC - Network address name, char 23-23
Word 32 00000 (0000) Remote PLC - Network address name, char 24-25
Word 33 00000 (0000) Remote PLC - Network address name, char 26-27
Word 34 00000 (0000) Remote PLC - Network address name, char 28-29
Word 35 00000 (0000) Remote PLC - Network address name, char 30-31
Word 36 - 51 Reserved: set to zero
The term local PLC is
used here to identify the
client PLC-the PLC
that initiates the
communications
request.
The term remote PLC
is used here to identify
the server PLC -the
PLC that responds to
the request.