03/05 AWB2724-1453GB
Data remanence
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Data remanence
The controller has a memory area for remanent data a page 10.
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 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
The following summary provides you with the state definitions for
the XC100. The LED indications for the various states are also
shown.
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
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