Function library
Function blocks
9.2.14 Holding brake (BRK)
9-71
L
EDSVS9332S-D11 EN 3.0
9.2.14 Holding brake (BRK)
Danger!
Condition for applying the BRK function block
Exclusively triggering the holding brake via the function block BRK is not permissible!
The safe triggering of theholding brake additionally requires asecond switch-off mode. Without the
second switch-off mode there is a risk of severe personal injury and danger to material assets!
Applications with active loads
With an increase of the DC-bus voltage (e.g. by braking processes) the torque limitation may
intervene due to code C0172. The torque limitation is activated if e.g.
z the brake resistor is damaged.
z the switching threshold set at the brake chopper or brake module is not adapted correctly.
Code C0172 is a pre-stage of the monitoring function “OU” (overvoltage of the DC-bus voltage).
Code C0172 defines which differential mode voltage causes a reduction in torque before OU. With
thedefault setting thetorque is reduced to ”0” if theDC-bus voltage amounts to 760 V(770 V - 10 V):
z OU threshold = 770V (C0173 = 0...3)*
z C0172 = 10 V
z No message is generated.
Only after the DC-bus voltage is decreased below the OU reclosing threshold the torque is
reconnected.
With unchanged basic conditions the continuously ”chopping” drive behaviour may lead to
undefined motions.
Remedy:
6. Set C0172 = 0 V
7. MONIT-OU must generate EEr-TRIP (e.g. with C0871/0 = 15011).
This serves to apply the standstill brake over the controller inhibit (CINH) if the braking energy
cannot be dissipated.
*) Exception: OU threshold 800 V with C0173 = 4 (see description in code table)
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