Siemens SINUMERIK 840D sl Equipment Manual page 31

Additional information on the diagnostics buffer is provided in the Function Manual Basic
Functions, see PLC signal DB10 DBX109.6 (fan temperature alarm).
Fans
The temperature is sensed at several locations within the NCU. The fan is automatically switched
in when the temperature thresholds set in the factory are exceeded. A hysteresis function
prevents frequent fan start/stop operations.
If natural convection is not sufficient to ensure cooling of the NCU, the fans integrated in the dual
fan/battery module are switched on when required (except for an NCU 730.3B PN with PLC
319-3 DP/PN, in this case, the fan runs continuously):
After switching the NCU on, the fan is activated for a brief period of time (function test) before
turning itself off again.
Note
The NCU cannot be operated without fans, i.e. it will not power up if the dual fan/battery module
is not functioning. The RDY LED flashes red/orange with 0.5 Hz, all other LEDs light up orange.
The state can only be exited by switching the NCU off.
Battery
A 3 V lithium battery is installed in the dual fan/battery module; this can be replaced when
required. The battery capacity of the 3 V lithium battery in the 840D sl is 950 mAh. The battery
is pre-assembled with an approximately 4 cm long cable with plug connector. The appropriate
mating connector is attached to a small circuit board for connection in the dual fan/battery
module.
Note
Please dispose of used batteries in the specially provided collection points on site. This will
ensure that the batteries are recycled in the correct manner or treated as special waste.
Note
The buffer time of an inserted battery is at least 3 years. If this buffer time is exceeded, the
internal PLC time is lost and must be reset after switching on.
NCU 7x0.3B PN
Equipment Manual, 10/2020, 6FC5397-1EP40-6BA1
Description
3.5 Dual fan/battery module
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