MSG
ABCDEFGHIJKLMNOP
7-28
Section
Special Instructions
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.
Flags
ER:
Indirectly addressed DM word is non-existent. (Content of
*
DM word is
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.
MSG(46)
DM 0010
FAL(06) 00
00000
00001
Address
Instruction
Operands
00000
LD
00000
00001
MSG(46)
DM
0010
00002
LD
00001
00003
FAL(06)
00
DM contents
ASCII
equivalent
DM 0010
4
1
4
2
A
B
DM 0011
4
3
4
4
C
D
DM 0012
4
5
4
6
E
F
DM 0013
4
7
4
8
G
H
DM 0014
4
9
4
A
I
J
DM 0015
4
B
4
C
K
L
DM 0016
4
D
4
E
M
N
DM 0017
4
F
5
0
O
P
7-28-2
I/O REFRESH – IORF(97)
St
: Starting word
IR 000 to IR 019
Ladder Symbol
E
: End word
IR 000 to IR 019
Operand Data Areas
IORF(97)
St
E
Note
This instruction is not supported by SRM1(-V2) PCs.
Limitations
St must be less than or equal to E.
Message Buffering and
Priority
Clearing Messages
Example
