7 Additional settings
7.11
Configuration of the DC bus monitoring
function
In special cases, the DC bus voltage may become too high or too low. If the DC bus
voltage becomes too high (overvoltage), an integrated brake chopper activates a parallel
resistor in a first step. If the voltage continues to rise, the servo drive will be switched off
due to overvoltage and the drive coasts down.
Risk of irreparable damage to the drive
If the servo drive is deactivated due to overvoltage, the driven component will not be
actively decelerated any longer. Instead it will coast down. In the case of limited ranges
of movement, the stops and the machine may be damaged.
Start with small acceleration values and increase them gradually. For analysis, check
the I²t indicator in the status window in order to be able to detect an overload of the
internal brake resistor in time.
The overvoltage switch-off threshold is factory-set and cannot be changed.
In addition, it is possible to trigger an error if the DC bus voltage is too
low
, provided that
this has been parameterised by the operator. The menu can be activated under
Parameters/Device parameters/Intermediate circuit control
.
Figure 112: "Intermediate circuit control" window
The field
Switching threshold
can be used to define the value below which the voltage
must fall so that the servo drive detects an undervoltage.
The flag that is set in the servo drive can be read by way of several different status
enquiries. For example, a digital output can be parameterised so that it indicates an
undervoltage event in the DC bus. See section 7.8
Product manual BL 4000-C
Page 184 of 298
