SECTION EIGHT – Safety function RESTART INTERLOCK (Optional)
DS2000 USER’S MANUAL (rev.C)
8.3
The Restart Interlock function is included in the drive and allows to not power-off the drive
and to skip the standard restart procedure.
The Restart Interlock safety function prevents motor unexpectedly starting from standstill.
This circuit can be used in the “Safe Standstill” machine function. When the motor is rotating,
the switching-on of the Restart Interlock provides an uncontrolled stop (category 0 according
to EN 60204-1:1997).
When a controlled stop of category 1, according to EN 60204-1:1997, is requested, the
condition of stopped motor must be assured. The external machine control must be able to
stop the motor (see par.2.14).
When the intervention time of the safety devices can be set up, appropriate precautions must
be adopted to limit the use only to qualified personnel. The intervention time of the restart
interlock safety function must be higher than the bracking time of the deceleration ramp set
by the drive with the maximum speed and the maximum load at the axis.
When active, the restart interlock function does not provide any more an output torque and
the motor is free to rotate. Adequate protections must be provided when external forces act
on the axis (e.g. gravity force on vertical axes), as a self-locking mechanical system or a
weight equalization system.
The restart interlock function does not provide electrical isolation. It does not provide
protection against "electric shock". The complete machine or system must always be
electrically isolated from the line supply through the main disconnection device, secured on
the open position, before any work is carried out on the machine or system, e.g.
maintenance, service or cleaning work (refer to EN 60204-1:1997, par. 5.3). Personnel must
be aware that Bus Bar's can have dangerous voltage even after switching off (capacitive
voltage) and the discharge time is approx. 6 minutes.
When correctly used, the restart interlock function must be looped in the line contactor circuit
in order to switch off the power supply of the axis in case of fault.
The associated drive must be electrically isolated from the supply if the restart interlock relay
function is not plausible (input and output not compatible). Only after the fault has been
removed, the restart interlock and the associated operating mode may be used again.
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