CTI 2572-A, Installation And Operation Manual

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CTI 2572-A Installation and Operation Guide V1.3 45
Create Socket Command Block
This command block creates a Multicast socket that will send to multicast address 225.1.1.1.
(0xE1010101).
Offset Description Hex Decimal
0 Error Word 0000 0
1 Command Code (Create Socket) 0003 03
2 Connection Number (19221 - 19228) 4B15 19221
3 Protocol Manager Number 0024 36
4 Startup Option Bits 0000 0
5 Type of Service (1 = TCP, 2 = UDP/Multicast)) 0002 2
6 Remote Device or Multicast IP Address- High 16 bits E101 57601
7 Remote Device or Multicast IP Address - Low 16 bits 0101 257
8 Unused (Set to 0) 0000 0
9 TCP/UDP Port Number 05E1 1505
10-15 Unused (Set to 0) 0000 0
Word Transfer Command Block
The following command block writes 25 words obtained from local PLC V memory starting at V100
to the a block of V memory starting at V200 in all PLCs that have a 2572-A module listening at IP
multicast address 225.1.1.1. The Unacknowledged Write command is used to prevent multiple
replies.
Offset Description Hex Decimal
0 Error Word 0000 0
1 Command Code (Write) 0201 516
2 Connection Number (19221 - 19228) 4B15 19221
3 Source: Starting V Memory Address in this PLC 0064 100
4 Number of Words to Transfer (1-256) 0019 25
5 Destination: Starting V Memory Address in Remote PLC 00C8 200
6 Command Timeout in seconds
(0 = Use Default)
0000 0
7-15 Unused (Set to 0) 0000 0
Since the command is not acknowledged, you cannot directly verify that the data was actually written
to the remote PLCs by monitoring the error status. Since most multicast applications will send the
same data periodically, lack of verification may be less important. If you wish to verify that data is
written you must use TCP or UDP unicast addresses, as illustrated in the previous examples, or you
may program the remote PLCs to send verification messages.