7-2
Section
Using Message Communications
96
Area
Allowed range
Data area specifier
(Hex)
Address
(Hex)
IR Area
IR 000 to IR 511
80
0000 to 01FF
Link Area
LR 00 to LR 63
80
03E8 to 0427
Holding Area
HR 00 to HR 99
80
0428 to 048B
Auxiliary Area
AR 00 to AR 27
80
048C to 04A7
Timer/counter
PVs
TIM/CNT 000 to
TIM/CNT 511
81
0000 to 01FF
DM Area
DM 0000 to DM 6655
82
0000 to 19FF
EM Area
EM 0000 to EM 6143
98 (Current bank),
90 to 97 (banks 0 to 7),
A8 to AF (banks 8 to 15)
0000 to 17FF
Use t Master Unit’s Message Communications Enabled Flag as an execution
condition for IOWR. Be sure this Flag is ON before executing IOWR. If this Flag
is OFF, a Special I/O Unit error may occur.
Execution
condition
Message
Communications
Enabled Flag
Equals Flag
IOWR
A
B
A
B
25506
Note Use the Equals Flag (SR 25506) to execute the instruction again when IOWR
execution ends in an error. The status of the Equals Flag can be changed by oth-
er instructions; be careful of its location in the program.
Communications Flags
The following table shows the flags that are normally used when executing
IOWR.
Flag
Address
Functions
Equals Flag
C200HX/HG/HE:
SR 25506
The Equals Flag turns OFF when an
error occurs in writing a command from
the CPU Unit to the Master Unit.
This Flag turns ON after a command has
been written normally from the CPU Unit
to the Master Unit.
Error Flag
C200HX/HG/HE:
SR25503
The Error Flag is OFF when all operands
and the control code are legal.
This Flag turns ON when an illegal
operand or control code is set (see note
1) or when there is an error in instruction
execution.
Message
Communications
Enabled Flag in the
Master Unit status
area
CS1-series:
Bit 12 in CIO 2001
+ (10 x unit No.)
C200HX/HG/HE:
Bit 12 in IR 101 +
(10 x unit No.)
The Communications Enabled Flag turns
OFF during messages communications
or when message communications are
not possible.
This Flag is ON when message
communications are possible.
Note
1. The number of words to write in D is not BCD or is not between 1 and 127.
With indirect DM addressing, the DM contents are not BCD or exceed 6556.
Using IOWR