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4-6 TCP/IP Ethernet Communications for the Series 90™ PLC User's Manual
–
May 2002 GFK-1541B
4
TASK:
For the Series 90-30 Ethernet Interface this must always be set to zero.
Caution
Entering an incorrect TASK value may cause the Ethernet Interface to fail.
FT Output:
The FT output is set if the PLC CPU (rather than the Ethernet Interface) detects that
the COMMREQ fails. In this case, the other status indicators are not updated for this
COMMREQ.
The COMMREQ Command Block
When the COMMREQ function is initiated, the Command Block is sent from the PLC CPU to the
Ethernet Interface. The Command Block contains the details of a command to be performed by
the Interface.
The address in CPU memory of the Command Block is specified by the IN input of the
COMMREQ Function Block. This address can be any valid address within a word-oriented area
of memory (%R, %AI, or %AQ for the Series 90-30 Ethernet Interface). The Command Block is
usually set up using the BLOCK MOVE programming instruction.
The Command Block has the following structure:
Word 1 Data Block Length (words)
Word 2 WAIT/NOWAIT Flag
Word 3 CRS Word Memory Type
Word 4 CRS Word Address Offset
Word 5
Reserved
Word 6
Reserved
Words 7 and up Data Block (Channel Command Details)
When entering information for the Command Block, refer to these definitions:
(Word 1) Data Block Length:
This is the length in words of the Data Block portion of the
Command Block. The Data Block portion starts at Word 7 of the Command Block. The length is
measured from the beginning of the Data Block at Word 7, not from the beginning of the
Command Block. The correct value for each command, and the associated length of each
command, is specified in the next section.
(Word 2) WAIT/NOWAIT Flag:
This flag must be set to zero for TCP/IP Ethernet
Communications.