8400 BaseLine D | Software Manual
Motor control (MCTRL)
DC-injection braking
102 L Firmware 03.00 - DMS EN 5.0 - 07/2009
5.6.2 Automatic DC-injection braking (Auto-DCB)
"Automatic DC-injection braking" (in the following called "Auto-DCB") can be used when
the drive has to be deenergised at n
≈ 0.
Function
For understanding the "Auto-DCB" function, it is necessary to distinguish between three
different types of operation:
1. When the drive is enabled and the speed setpoint falls below the Auto-DCB threshold
during operation, a braking current C036
is injected. When the Auto-DCB hold time
C106
has expired, the motor is deenergised via the Auto-DCB function, i.e. the
controller inhibit (CINH) is set.
2. At the moment of controller enable, the drive is at standstill (n = 0).
If the enabled drive is to start up, the speed setpoint passed via the acceleration ramp
must exceed the Auto-DCB threshold C019
. Below this threshold, the motor will not be
energised.
3. At the moment of controller enable, the motor (still) rotates with a speed above the
Auto-DCB threshold and the drive is "caught".
For more detailed information on the topic see
Flying restart function
( 98).
How to set the automatic DC-injection braking
1. Set the hold time in code C106
to t > 0.0 s
• Automatic DC-injection braking is active for the time set.
• A braking current is injected (code C036
).
• When the hold time C106
has expired, the controller sets the pulse inhibit.
2. Set the response threshold with C019
. This code can be used to set a dead band in
the setpoint. If DC-injection braking is not to be active here, C106
must be set to
the value "0.0".
Stop!
If the DC-injection braking operation is too long and the braking current or
braking voltage is too high, the connected motor may overheat.
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