Phoenix Contact 2702772, User Manual

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GW EIP/ASCII...
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PHOENIX CONTACT 3785_en_B
6.4 Receive data message
When connecting to MicroLogix, PLC-5, and SLC PLCs, “Receive Data” messages are
formatted in 16-bit integer format.
6.4.1 Received message characteristics
Received messages return all data in UINTs.
The data length field indicates the number of valid bytes contained in the message.
Messages received from the PLC determine the actual length of the message returned to
the PLC. This is often greater than the length of the actual “Receive Data” message.
All unused bytes in a message returned to the PLC are filled with zeros.
The default order of the bytes is least significant byte first.
The GW EIP/ASCII... supports serial packets of up 1518 bytes and socket packets up to
2048 bytes when Write to Tag/File is selected in the “Transfer mode to PLC” field.
When large packets of data are received, the data is automatically placed in sequential files.
The files must be 256 integers in size with the exception of the last file. The last file may be
shorter than 256 integers as long as the total length of all files in the sequence is sufficient
to hold the largest receive packet, plus two integers for the sequence number and length
parameters. The sequence number is updated when all data is transferred to the PLC.
Table 6-4 Receive data message format
Name Data type Data value Access rule
Structure of:
Product data sequence
number
UINT 0 - 65535 (FFFF
hex
) Read/Write
Data length (bytes) UINT 0 - 222 (SLC), 0 - 248
PLC-5)
Read/Write
Data array Array of UINT 0 - 65535 Read/Write