Efficient Networks S120 manual Description of Vdcmax control without acceleration p1240 = 7

Servo control 3.14 Vdc control

feed energy back, the drives with an active Vdc_max controller can even be accelerated to absorb the braking energy and, in turn, relieve the DC link.

Description of Vdc_max control without acceleration (p1240 = 7, 9)

As with p1240 = 1, 3, if the drive must not be accelerated by means of feedback from other drives in the DC link, acceleration can be prevented by the setting p1240 = 7, 9. The effective lower torque limit must not be greater than the torque limit offset (p1532).

Description of Vdc controller monitoring functions (p1240 = 4, 5, 6)

In the event of a power failure, the Line Module can no longer supply the DC link voltage, particularly if the Motor Modules in the DC link line-up are drawing active power. To ensure that the DC link voltage is not burdened with uncritical drives in the event of a power failure, these drives can be switched off by a fault (F30003) with a parameterizable voltage threshold (p1248). This is carried out by activating the Vdc_min monitoring function (p1240 = 5, 6).

In the event of a power failure, the DC link voltage can increase until it reaches the shutdown threshold when drives are decelerated. To ensure that the DC link voltage is not burdened with uncritical drives in the event of a power failure, these drives can be switched off by a fault (F30002) with a parameterizable voltage threshold (p1244). This is carried out by activating the Vdc_max monitoring function (p1240 = 4, 6).

Function diagrams (see SINAMICS S List Manual)

● 5650 Vdc_max controller and Vdc_min controller

Overview of key parameters (see SINAMICS S List Manual)

Adjustable parameters

●p1240 Vdc controller or Vdc monitoring configuration

●p1244 DC link voltage threshold, upper

●p1248 DC link voltage threshold, lower

●p1250 Vdc controller proportional gain

Display parameters

●r0056.14 Vdc_max controller active

●r0056.15 Vdc_min controller active

Drive Functions	105
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4