12.1.2 Command Block for the COMMREQ Function
The Command Block starts at the reference specified in COMMREQ parameter IN. The
length of the Command Block depends on the amount of data sent to the device.
The Command Block contains the data to be communicated to the other device, plus
information related to the execution of the COMMREQ. The Command Block has the
following structure:
address
Length (in words)
address + 1
Wait/No Wait Flag
address + 2
Status Pointer Memory
address + 3 Status Pointer Offset
address + 4 Idle Timeout Value
address + 5 Maximum Communication Time
address + 6 to
address + 133
Data Block
12.1.3 Example of the COMMREQ Function
In the example, when %M0021 is ON, a Command Block located starting at %R0032 is
sent to port 2 (communications task 20) of the CPU (rack 0, slot 0). If an error occurs
processing the COMMREQ, %Q0110 is set.
%M0021
| |
COMM_
REQ
IN
CONST
0000
SYSID
Serial I/O / SNP / RTU Protocols GFK-1503E User Manual 227
For public disclosure
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