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FX Series Programmable Controllers Execution Times And Instructional Hierarchy 7
7-15
b) Data Memor
y
This memor
y
area contains, as the title su
gg
ests, all of the data values associated with:
data re
g
isters (normal and special), Index re
g
isters, current timer values, retentive timer
values (if available) and current counter values.
- All of the devices which are desi
g
nated as bein
g
latched (includin
g
retentive timers) are
backed up in a similar method to the one mentioned under point a).
- Index re
g
isters and special data re
g
isters (D8000 to D8255) operate in the specified
manner under the followin
g
circumstances:
- All other devices such as current values of non latched data re
g
isters, timers and
counters behave in the followin
g
manner:
c) Bit Memor
y
This memor
y
area contains the contact status of all inputs, outputs, auxiliar
y
rela
y
s, state coils,
timers and counters.
- All of the devices which are desi
g
nated as bein
g
latched (includin
g
retentive timers) are
backed up in a similar method to the one mentioned under point a).
- Special auxiliar
y
rela
y
s (M8000 to M8255) act in a similar wa
y
to the special data
re
g
isters mentioned under point b).
- All other devices are sub
j
ect to the same chan
g
es as the current values of data re
g
isters,
timers and counter (see the last point and table under section b).
Summary
Circumstance Reaction
PLC's power is turned OFF All data is cleared
PLC's power is turned ON Certain devices are reset to their defaults see chapter 6
PLC is switched from STOP to RUN
Certain devices are reset to their defaults see chapter 6
PLC is switched from RUN to STOP
Circumstance Reaction
PLC's power is turned OFF
All data is cleared
PLC's power is turned ON
PLC is switched from STOP to RUN No chan
g
e
PLC is switched from RUN to STOP Cleared (unless special M coil M8033 is active)
Memory type
Power PLC
OFF OFF ON STOP RUN RUN STOP
All devices backed b
y
batter
y
Not chan
g
ed
Special M and D devices (8000 to
8255) and index re
g
isters V and Z
Cleared Default Not chan
g
ed
All other devices Cleared
Not chan
g
ed Cleared
Not chan
g
ed when M8033 is set