Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual page 516

Special Instructions
Message Buffering and
Priority
Clearing Messages
Flags
Example
00000
00001
DM contents
DM 0010 4 1
DM 0011 4 3
DM 0012 4 5
DM 0013 4 7
DM 0014 4 9
DM 0015 4 B
DM 0016 4 D
DM 0017 4 F
7-28-2 I/O REFRESH – IORF(97)
Limitations
498
Up to three messages can be buffered in memory. Once stored in the buffer, they
are displayed on a first in, first out basis. Since it is possible that more than three
MSG(46)s may be executed within a single cycle, there is a priority scheme,
based on the area where the messages are stored, for the selection of those
messages to be buffered.
The priority of the data areas is as follows for message display:
LR > IR > HR > AR > TC > DM
In handling messages from the same area, those with the lowest ad-
dress values have higher priority.
In handling indirectly addressed messages (i.e. *DM), those with the
lowest final DM addresses have higher priority.
To clear a message, execute FAL(06) 00 or clear it via a Programming Console
or the Support Software.
If the message data changes while the message is being displayed, the display
will also change.
Indirectly addressed DM word is non-existent. (Content of *DM word is
ER:
not BCD, or the DM area boundary has been exceeded.)
The following example shows the display that would be produced for the instruc-
tion and data given when 00000 was ON. If 00001 goes ON, a message will be
cleared.
ASCII
equivalent
4 2 A B
4 4 C D
4 6 E F
4 8 G H
4 A I J
4 C K L
4 E M N
5 0 O P
Ladder Symbol
IORF(97)
St
E
Note This instruction is not supported by SRM1(-V2) PCs.
St must be less than or equal to E.
Address Instruction
MSG(46)
00000
DM 0010
00001
FAL(06) 00
00002
00003
Operand Data Areas
Section
Operands
LD
MSG(46)
DM
LD
FAL(06)
St: Starting word
IR 000 to IR 019
E: End word
IR 000 to IR 019
7-28
00000
0010
00001
00