9
05.01
9.12 Operation at power failure
9-296
Siemens AG 2001 All rights reserved
SIMODRIVE 611 Planning Guide (PJU) – 05.01 Edition
When configuring/engineering line supply failure concepts, the following
control and secondary conditions should be taken into account:
S The braking energy must be converted into heat using one or several
pulsed–resistor module(s) or for uncontrolled rectifier units, using the
internal pulsed resistor (an external resistor may be additionally required).
When the drives brake, it is not permissible that the DC link voltage violates
the max. set monitoring thresholds.
S At power failure, the safety–related hardware control must briefly maintain,
e.g. the enable signals via terminals 48, 63, 64, NS1, NS2 and 663. Further-
more, the internal, axis–specific enable signals of the NC/PLC interface
must also be kept until the drives come to a standstill via the digital drive
bus.
S For controlled retraction movements, if required, until the operation has been
completed, holding brakes must remain energized and mechanical clamps
must released.
S The external +24 V power supply for the control voltage must be buffered,
using power supply units, e.g. SITOP power with capacitor or battery back–
up in order to maintain the drive enable signals, the PLC functions and the
open–loop control and machine functions on the user side.
S During the braking and retraction phases, it is not permissible that the NC
and PLC controls generate fault/error signals which inhibit the drives.
S The power supply of the SINUMERIK 840 D with integrated PLC–CPU is
supplied through the NE module DC link when the line supply fails. The
SINUMERIK 840C power supply with 115–230V AC or 24V DC must be
separately buffered.
Information on the subsequent circuit example, Fig. 9-31
Terminals P500,M500 for the auxiliary power supply in the NE module and
monitoring module must be connected to the power DC link P600,M600 using
short–circuit proof cables, which are twisted and shielded in compliance with
EMC Guidelines. The cable shields should be connected to the mounting panel
at both ends through the largest possible surface area.
Cross–section: 1.5 mm@ , max. cable length: 3 m.
Notice
In order to safely and electrically isolate the DC link from the line supply, when
the line contactor is opened or when changing over to the setting–up mode,
the connection P600,M600 to terminals P500,M500 must be reliably and
safely disconnected, e.g. via the power contacts of contactor –K1, also refer to
Section 9.2.4.
This is also valid for the connection to terminals P500,M500 when using
monitoring modules.
Contactor –K1 must be safely de–energized via the drive EMERGENCY STOP,
OFF functions together with the power–off function of the internal line contactor
in the NE module or when changing over the operating mode to setting–up.
9 Important Circuit Information
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