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Data remanence
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Data remanence
The controller has a memory area for remanent data
The variables declared with “VAR_RETAIN” are saved in this area
and are thus retentive during a warm start of the application
program (Caution: This does not apply for I, Q and M variables!).
Data that are remanent for a cold start – “VAR_RETAIN
Persistent” are not supported. Remanence (non-volatility) of the
data is guaranteed when the PLC is switched off if a battery is
inserted.
If it was not possible to finish a cycle that was being processed,
because of a supply interruption, then the data will not be
consistent, since the interruption could have occurred at any point
of the cycle. When the voltage supply recovers, the residual-cycle
will not be completed. The control starts according to the set start
behaviour.
If this is to be prevented, appropriate measures must be taken as
part of the engineering. One solution for this problem is an
uninterruptible power supply with additional accumulator
buffering.
Program transfer
The transfer of an application program always takes place via the
battery-buffered SRAM area in the controller. Afterwards, a
backup can be created on the multimedia card by using the
“Create boot project” command. A program backup can only be
created while the system is in the “HALT” state. The internal
FLASH memory of the CPU cant be used as storage for a program
backup.
Operating states
In the following overview you will find the state definitions of
XC100. The LED-displays of the corresponding states are also
detailed..
State
Display
Definition
RUN/STOP
SF
System test
off
off
System test in
progress
System update
on
on
System update in
progress
Switch-on OK
off
off
System test finished
without error
Switch-on not OK
blinks
blinks
System test generated
an error
NOT READY
off
on
No application
program present
STOP
blinks
off
Application program
loaded, PLC in
“STOP” state
RUN
on
off
Application program
loaded, PLC in “RUN”
state
STOP/RUN with
general error,
diagnosis
message
on
on
General error/
diagnosis message
available
Содержание XC200 Series
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