!
44
3-4-13 Step Flag
SR bit 25407 turns ON for one cycle when step execution is started with the
STEP(08) instruction.
3-4-14 Group-2 Error Flag
SR
bit 25414 turns ON for any of the following errors for Group-2 High-density
I/O Units and B7A Interface Units: the same I/O number set twice, the same
words
allocated to more than one Unit, refresh errors. If one of these errors oc
-
curs,
the Unit will stop operation and the
ALARM indicator will flash, but the over
-
all PC will continue operation.
When
the Group-2 Error Flag is ON, the number of the Unit with the
error will be
provided in AR 0205 to AR 0214. If the Unit cannot be started properly even
though
the I/O number is set correctly and the Unit is installed properly
, a fuse
may be blown or the Unit may contain a hardware failure. If this should occur,
replace the Unit with a spare and try to start the system again.
There
is also an error flag for High-density I/O Units and B7A Interface Units
in
the AR area, AR 0215.
3-4-15 Special Unit Error Flag
SR
bit
25415 turns ON to indicate errors in the following Units: Special I/O, PC
Link,
Host Link, and Remote I/O Master Units. SR bit 25415 will turn ON for any
of the following errors.
• When more than one Special I/O Unit is set to the same unit number.
• When an error occurs in refreshing data between a Special I/O Unit and the
PC’s
CPU.
• When an error occurs between a Host Link Unit and the PC’
s CPU.
• When an error occurs in a Remote I/O Master Unit.
Although
the PC will continue operation if SR 25415 turns ON,
the Units causing
the
error will stop operation and
the ALM indicator will flash. Check the status of
AR
0000 to AR 0015 to obtain the unit numbers of the Units for which the error
occurred and investigate the cause of the error.
Unit
operation can be restarted by using the Restart Bits
(AR 0100 to AR 01
15,
SR
25207, and SR 25213), but will not be ef
fective if the same unit
number is set
for more than one Special I/O Unit. Turn off the power supply, correct the unit
number settings, and turn of the power supply again to restart.
SR
25415 will not turn OFF even if AR 0100 to AR 01
15 (Restart Bits) are turned
ON.
It can be turned OFF
by reading errors from a Programming Device or by
executing FAL(06) 00 from the ladder program.
3-4-16 Instruction Execution Error Flag, ER
SR
bit 25503
turns ON if an attempt is made to execute an instruction with incor
-
rect
operand data. Common causes of an instruction error are non-BCD oper
-
and
data when BCD data is required, or an indirectly addressed DM word that is
non-existent. When the ER Flag is ON, the current instruction will not be
executed.
3-4-17 Arithmetic Flags
The
following flags are used
in data shifting, arithmetic calculation, and compari
-
son
instructions. They are generally referred to only by their two-letter
abbrevia
-
tions.
Caution These
flags are all reset
when the END(01) instruction is executed, and therefore cannot be moni
-
tored from a programming device.
Refer
to
5-15
Data Shifting
,
5-17 Data Comparison
,
5-19 BCD Calculations
, and
5-20 Binary Calculations for details.
SR Area Section 3-4
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