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8 Important Circuit Information
8.7 Circuit examples =1 to =9 with SIMODRIVE 611
8-282
In the circuit examples, for a drive stop, the holding brake is disconnected
with drop–out delay using the appropriate hardware in addition to the PLC
control. This means that a PLC fault cannot result in the brake being incor-
rectly controlled when the drive is stationary. It must be decided, on an ap-
plication–for–application basis, whether when stopping in emergency, the
brake is to be shutdown instantaneously or with a delay. Using an internal
sequence control, 611U controls allow a holding brake to be controlled in a
coordinated way (refer to the Function Description for SIMODRIVE 611 uni-
versal).
Holding brakes must be provided with external circuitry to dampen overvol-
tages.
For detailed description, refer to the Configuration Manual for SIMODRIVE
motors.
S
Safe standstill
After the drives have stopped, by safely disconnecting the power feed to the
motors, the drives are in the safe standstill condition. When the start inhibit is
activated, then the pulses are safely cancelled in the drive modules.
Features
– The motor cannot be started accidentally.
– The power feed to the motor is safely disconnected
– The motor is not electrically isolated from the drive module or the con-
verter DC link.
The machinery construction OEM must take the appropriate measures to
ensure that the drives do not undesirably move after the power feed has
been disconnected.
Secondary conditions, e.g. for vertical/suspended axes:
– Safe standstill is only guaranteed if the kinetic energy stored in the ma-
chine cannot result in an unpredictable motion of the drives/axes. For
example, for vertical or inclined axes without weight equalization, motion
can occur as a result of non–symmetrical rotating bodies or workpieces.
– The motor holding brake supports the safe standstill operating mode.
– When manually intervening in the automatic mode, when traversing in
setup mode, as well as during service/maintenance and repair work,
depending on the hazard analysis, it may be necessary to apply addi-
tional measures for personnel and machinery protection.
– Axes can be secured from dropping/falling or axes can be locked in a
specific position using redundant devices in addition to the holding
brake, e.g. using electromechanical or pneumatic locking devices with
cyclic monitoring.
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
© Siemens AG 2012 All Rights Reserved
05.01
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