GE GFK-1541B manual Reserved

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TASK: For the Series 90-30 CPU364, this must always be set to 21 decimal (0015H). For the Series 90-30 Ethernet Interface and the Series 90-70 Ethernet Interface (Type2), this must always be set to zero.

Caution

Entering an incorrect TASK value may cause the Ethernet Interface to fail.

OK Output: (Series 90-70 PLC only) The OK output is set if the PLC CPU has successfully delivered the COMMREQ to the Ethernet Interface.

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 Channel 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 and the Series 90-30 CPU364) (%R, %AI, %AQ, %P, or %L for the Series 90-70 Ethernet Interface (Type 2)). The Command Block is set up using an appropriate programming instruction (the BLOCK MOVE or DATA_INIT (Series 90-70 PLC only) Function Blocks are recommended).

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.

GFK-1541B Chapter 3 Programming Channel Commands 3-7