Omron CS1G/H-CPUxxH Instructions Manual page 905

Network Instructions
Precautions
Example 1
884
The following table shows relevant bits and flags in the Auxiliary Area.
Name Address
Communications A20200 to
Port Enabled Flag A20207
Communications A21900 to
Port Error Flag A21907
Communications A203 to
Port Completion A210
Codes
If the Communications Port Enabled Flag is OFF for the port number specified
in C+3, the instruction will be treated as NOP(000) and won't be executed.
The Error Flag will be turned ON in this case.
When an address in the current bank of the EM Area is specified for D, the
transmitted data will be written to the current EM bank of the destination node.
When data will be transmitted outside of the local network, the user must reg-
ister routing tables in the PLCs (CPU Units) in each network. (Routing tables
indicate the routes to other networks in which destination nodes are con-
nected.)
Refer to the FINS command response codes in the CS/CJ Series Communi-
cations Commands Reference Manual (W342) for details on the completion
codes for network communications.
Only one network instruction may be executed for a communications port at
one time. To ensure that SEND(090) isn't executed while a port is busy, pro-
gram the port's Communications Port Enabled Flag (A20200 to A20207) as a
normally open condition.
Communications port numbers 00 to 07 are shared by the network instruc-
tions and PMCR(260), so SEND(090) cannot be executed simultaneously
with PMCR(260) if the instructions are using the same port number.
Noise and other factors can cause the transmission or response to be cor-
rupted or lost, so we recommend setting the number of retries to a non-zero
value which will cause SEND(090) to be executed again if the response is not
received within the response monitoring time.
When the input condition and A20200 (the Communications Port Enabled
Flag for port 0) are ON in the following example, the ten words from CIO 100
to CIO 109 are transmitted to the host computer connected to port 1 of the
Serial Communications Unit with unit address 10 (Hex) at node number 3 in
network 0.
Operation
These flags are turned ON to indicate that net-
work instructions, including PMCR(260) may be
executed for the corresponding ports (00 to 07).
A flag is turned OFF when a network instruction is
being executed for the corresponding port and
turned ON again when the instruction is com-
pleted.
These flags are turned ON to indicate that an
error has occurred at the corresponding ports (00
to 07) during execution of a network instruction.
The flag status is retained until the next network
instruction is executed. The flag will be turned
OFF when the next instruction is executed even if
an error occurred previously.
These words contain the completion codes for the
corresponding ports (00 to 07) following execution
of a network instruction.
The corresponding word will contain 0000 while
the network instruction is being executed and the
completion code will be written when the instruc-
tion is completed. These words are cleared when
an instruction is executed.
Section 3-25