Lenze 8400 TopLine - Manual (Page 1555)

Lenze · 8400 TopLine · Reference manual · DMS 6.0 EN · 06/2014 · TD05/TD14
1555
19 Function library
19.1 Function blocks
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
19.1.106.3 Activating the mains failure control
The mains failure control is activated by setting bFault to TRUE. The controller now generates the
required operational energy from the rotational energy of the drive. The drive is braked via the
power loss of the controller and the motor. Thus, the speed deceleration ramp is shorter than for an
uncontrolled system (coasting drive).
After activating the mains failure control:
1. The acceleration time set in C01470/2 is used to control the DC-bus voltage to the value at
nDCSet_a.
2. At nNOut_a, an internally generated speed setpoint is output which serves to brake the drive to
a speed close to "0" (via the speed setpoint).
• Starting value for the controlled deceleration is the value at nSet_a. This input is
appropriately connected to the actual speed value nMotorSpeedAct_a of the
SB LS_MotorInterface .
• The speed deceleration ramp (and hence the braking torque) results from the moment of
inertia of the load machine(s), the power loss of the drive (system) and the set parameter
setting.
Stopping/cancelling the mains failure control
When bFault is reset to FALSE, an internal timing element is triggered. After the time set in
C01470/3 has elapsed, the mains failure control is stopped/cancelled.
• When the restart protection is active, the drive is continued to be braked to standstill.  Restart
protection ( 1559)
• When the restart protection is active, the drive can only be reset by setting the bReset input
to TRUE.
• When the restart protection not active, the drive is accelerated to the speed setpoint.  Quick
mains recovery (KU) ( 1559)

Stop!
If a connected braking unit responds, the drive is braked with a max. possible torque
(I
max
). In this case, adapt the parameter setting if required (see the following chapter).
If the power section is not supplied, the drive cannot create a standstill torque
(important for active loads as e.g. hoists).