Siemens SINUMERIK 840D sl Function Manual page 453

Reboot delay
The reboot delay results in the NCK and PLC being shut down with a delay and
communicates the pending shutdown in order to prevent hanging (suspended) axes from
dropping.
Note
The reboot delay only works with a controlled POWER ON via the HMI.
The reboot delay is not activated for a POWER FAIL (power failure) or a hardware reboot.
Reboot sequence
The HMI initiates an NCK and PLC reboot using PI service "_N_IBN_SS".
NCK immediately activates alarm 2900 in response to the PI service.
Mechanical axis brakes can be activated in the time that the NCK allows to expire from the
PI service to the reboot (reboot delay time, refer to MD10088
$MN_REBOOT_DELAY_TIME).
Reactions to alarm 2900
● The following NC/PLC signals are canceled, i.e. set to zero:
● The "Ready" message at relay contacts 72 73.1 73.2 74 is not reset.
● The motor brakes along the current limit.
● The following NC/PLC interface signals remain at 1:
By using the machine data:
MD11410 $MN_SUPPRESS_ALARM_MASK (mask for suppressing special alarms) (BIT20)
the alarm 2900 is suppressed, however, the NCK triggers the same reactions.
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
– DB11 DBX 6.3 (mode group ready) ; all mode groups
– DB21, ... DBX 36.5 (channel ready) ; all channels
– DB31, ... DBX 61.2 (axis ready) ; all axes
For further details, see machine data:
– MD36610 $MA_AX_EMERGENCY_STOP_TIME (braking ramp time when errors
occur)
– MD36620 $MA_SERVO_DISABLE_DELAY_TIME (switch-off delay controller release)
Note
After the shutdown delay, the NCK withdraws the controller enable (MD36620) of the
position control.
DB10 DBX108.7 (NC ready)
5.8 Measures for hanging (suspended axes)
K3: Compensation
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