Lenze 8400 BaseLine D - Manual (Page 98)

5 Motor control (MCTRL)
5.6 Parameterisable additional functions
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Lenze · 8400 BaseLine D · Reference manual · DMS 5.5 EN · 01/2014 · TD05
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5.6.3.1 Manual DC-injection braking (DCB)
DC-injection braking can be manually activated via the bSetDCBrake process input.
• For HIGH-active inputs, DC-injection braking is active as long as the signal is at HIGH level.
• After the hold time ((
C107 ) has expired, the controller sets the pulse inhibit (CINH).

Tip!
• In the preset "Terminals 0" control mode, DC-injection braking can be manually activa-
ted via the digital input DI3.
• In the preset "Terminals 11" control mode, DC-injection braking can be manually activa-
ted via the digital input DI2.
5.6.3.2 Automatic DC-injection braking (Auto-DCB)
"Automatic DC-injection braking" (referred to in the following as "Auto-DCB") can be used if there is
a requirement that the drive be isolated from the supply at n
≈ 0.
Function
For understanding the auto-DCB function, it is necessary to distinguish between three different ty-
pes of operation:
A. The drive has been enabled and, in the course of operation, the speed setpoint falls below the
Auto-DCB threshold.
• In case of operation without speed feedback, a braking current ( C036 ) is injected. After the
auto-DCB hold time ( C106 ) has expired, the motor is deenergised via the auto-DCB function,
i.e. a controller inhibit (CINH) is set.
B. When the controller is enabled, the drive is at standstill (n = 0).
If the enabled drive is to start, the speed setpoint passed via the acceleration ramp must exceed
the auto-DCB threshold ( C019 ). Below this threshold, the motor will not be energised.
C. When the controller is enabled, the motor (still) rotates at a speed which is above the auto DCB
threshold. If the speed setpoint reached via the acceleration ramp exceeds the auto DCB thres-
hold C019 ), the motor will be energised and the drive will be "caught".  Flying restart function
( 95)

How to set the automatic DC-injection braking
1. Set a hold time in C106 > 0 s.
• Automatic DC-injection braking is active for the time set.
• In case of operation without speed feedback, the braking current set in
C036 is injected
• After the set hold time has expired, the controller sets a pulse inhibit.
2. Set the operating threshold in C019 .
• The operating threshold can serve to set a dead band in the setpoint. If DC-injection bra-
king is not to be active then, C106 must be set to a value of "0".