Rockwell Automation 1403-NDNET DeviceNet Communications Card Installation Instructions - Manual (Page 128)

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C-2 DeviceNet™ Communication Card Sample Ladder Listing
•
1 = Execute transaction block
•
4 = Delete transaction from response queue
A command byte of 1 is used first to start the explicit message. After a
response has been received from the scanner, a command byte of 4 is
used to remove this transaction from the scanner. If the command
byte of 4 is not written to the SLC-500 DeviceNet Scanner, then it does
not process further transactions.
Word M0:1.225
A port number and transaction body size is needed for this word. The
port number is the DeviceNet scanner port that handles this
transaction; an SLC-500 uses port 0 and the PLC-5 uses port 0 or 1.
The size is the number of bytes (2 bytes = 1 word) in the transaction
body which is 6 (6 bytes = 3 words).
Word M0:1.226
A service code and MAC ID is needed for this word. The service code
is the DeviceNet service that can be use on the Class 4 assembly
instances; the valid service codes are:
•
14 = Get_Attributes_Single
•
16 = Set_Attributes_Single
The MAC ID is the node number of the device that the DeviceNet
scanner is communicating to; this example will use node 5.
TXID Cmd
TXID x 256 + Cmd
11x 256 + 1
2817
Port Size
Port x 256 + Size
0 x 256 + 6
6