Lenze EVS9332xS - Manual (Page 167)

Function library
Function blocks
3.2.40 Mains failure control (MFAIL)
3−115
l
EDSVS9332S−EXT EN 2.0
Activation
l MFAIL−FAULT = HIGH activates the mains failure control.
l MFAIL−FAULT = LOW triggers a timing element. After the time set under C0983 has elapsed,
the mains failure control is completed/cancelled (see description of mains recovery,
chapter 3.2.40.6).
– The drive is accelerated to the speed setpoint if the restart protection is not active.
– The drive is continued to be braked to zero speed if the restart protection is active (see
description for restart protection, chapter 3.2.40.3).
– If the restart protection is active, the drive can only be reset by a HIGH level signal at the
MFAIL−RESET input.
Function
The controller generates the operational energy required from the rotational energy of the driving
machine. The driving machine is braked via the power loss of the controller and the motor. Thus, the
speed deceleration ramp is shorter than with a non−controlled system (coasting drive).
With the activation,
l the DC bus voltage is controlled to the value at the MFAIL−DC−SET input.
l An internally generated speed setpoint is output at output MFAIL−N−OUT. This serves to brake
the drive (via the speed setpoint) to a speed of almost zero.
– Starting value for the controlled deceleration is the value at input MFAIL−SET. This input is
generally connected to the output MCTRL−NACT (actual speed value) or MCTRL−NSET2,
MFAIL−NOUT (speed setpoint).
– The speed deceleration ramp (and thus the brake torque) results from the moment of inertia
of the driven machine(s), the power loss, and the parameterisation.
(
Stop!
l If a connected braking unit is activated, the drive is braked with the max. possible
torque (Imax). In this case, the parameter setting can be adapted, if required (see
description for parameter setting).
l If the power stage is not supplied, the drive cannot generate a standstill torque
(important for active loads such as hoists).