1033
Network Instructions Section 3-25
Example of Previous Programming Requirements
Now, for CS1-H, CJ1-H, CJ1M, and CS1D CPU Units of lot number 020601 or
later (manufactured 1 June 2002 or later), the port number can be specified
as “F” instead of from 0 to 7 to automatically allocate the communications
port, i.e., the next open communications port is used automatically.
This saves the programmer from having to keep track of communications
ports while programming. The differences between assigning specific port
numbers and automatically allocating port numbers are given in the following
table.
Execution
condition
d (Execution completed)
a (Executing)
b
(Executing)
Exclusive control was required by the user when
the same communications port was used more than once.
It was necessary to keep track of the communications
port being used by each instruction.
Confirmation of the availability of a communications port
was required using the corresponding Communications Port Enabled Flag, here for port 0.
A20200
b (Executing)
c (Executing)
Communica-
tions port: 1
KEEP
@Communica-
tions instruction
Communica-
tions port: 0
@Communica-
tions instruction
Communica-
tions port: 0
@Communica-
tions instruction
a
(Executing)
Exclusive control was required by the user when the same communications port was used more than once.
Item Specific number
assignments
Automatic allocation
Specification of the com-
munications port number
in the control data
0 to 7 F
Exclusive control Required. Not required unless more than 8
communications ports are
required at the same time.
Flag applications LD or LD NOT used
with flag corre-
sponding to the
specified communi-
cations port.
TST(350) or TSTN(351) used with
A218 (Used Communications Port
Number).
Network communica-
tions completion codes
Completion code for
communications
port specified by
user is accessed.
Completion codes are accessed
by using the I/O memory address
stored in A216 and A217 (Network
Communications Completion
Code Storage Address) and index
register indirect addressing.
Communica-
tions port: F
When “F” is specified, the next available
communications port is used automatically.
@Communica-
tions instruction
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