5
Deployment CPU 315-4PN23
5.1 Assembly
Information about assembly and cabling:
installation guidelines’ page 16
5.2 Start-up behavior
After the power supply has been switched on, the CPU changes to the operating mode
the operating mode lever shows.
When the CPU is delivered it has been reset. After a STOP
®
RUN transition the CPU
switches to RUN without program.
The CPU switches to RUN with the program stored in the battery buffered RAM.
n
The accumulator/battery is automatically loaded via the integrated power supply and
guarantees a buffer for max. 30 days. If this time is exceeded, the battery may be
totally discharged. This means that the battery buffered RAM is deleted.
n
In this state, the CPU executes an overall reset. If a memory card is plugged, pro-
gram code and data blocks are transferred from the memory card into the work
memory of the CPU. If no memory card is plugged, the CPU transfers permanent
stored "protected" blocks into the work memory if available.
n
Depending on the position of the operating mode switch, the CPU switches to RUN, if
OB 81 exists, res. remains in STOP. This event is stored in the diagnostic buffer as:
"Start overall reset automatically (unbuffered PowerON)".
CAUTION!
After a power reset and with an empty battery the CPU starts with a BAT
error and executes an overall reset. The BAT error can be deleted again,
if once during power cycle the time between switching on and off the
power supply is at least 30sec. and the battery is fully loaded. Otherwise
with a short power cycle the BAT error still exists and an overall reset is
executed.
Turn on power supply
Default boot procedure, as
delivered
Boot procedure with valid
configuration in the CPU
Boot procedure with
empty battery
System 300S
+
Deployment CPU 315-4PN23
Start-up behavior
HB140 | CPU | 315-4PN23 | en | 18-02
37
