Lenze 8400 StateLine - Manual (Page 154)

5 Motor control (MCTRL)
5.6 V/f control (VFCplus + encoder)
154
Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5.6 V/f control (VFCplus + encoder)
The V/f characteristic control (VFCplus) described above can be operated with a speed feedback.
This has the following advantages:
• Steady-state accuracy of the speed
• Less parameterisation effort compared to the sensorless vector control (SLVC)
• Improved dynamics compared to V/f characteristic control without feedback or to sensorless
vector control (SLVC).
• Suitability for group drives

Stop!
The V/f control requires a speed feedback!
• The speed sensor used has to be set in C00495 . This setting is not made automatically
with the selection of the motor from the »Engineer« motor catalogue!
• If no speed sensor is set in C00495 and the controller is enabled, an impermissibly
high motor current occurs which may destroy the motor thermally!
• From version 14.00.00 , the error response set in C00571/2 (Lenze setting: "Fault")
takes place if in case of controller enable it is detected that a motor control type with
feedback is set in C00006 but no speed encoder is set in C00495 .

Stop!
V/f emergency operation
From version 15.00.00 , it is internally switched to the encoderless V/f characteristic
control in case of an encoder open circuit in order to avoid impermissible motor
movements.
• In order that this "V/f emergency operation" works properly, the parameters relevant
for the V/f characteristic control (base frequency, Vmin boost, slip compensation, etc.)
have to be set correctly. As an alternative, a motor parameter identification can be
executed as well.
• The change-over to "V/f emergency operation" is reported via bit 4 in C01000 and via
the bWirebreakUfLinearActive status signal at the SB LS_DeviceMonitor .
• The change-over to "V/f emergency operation" can be suppressed by setting bit 8 to
"1" in C02864/1 .

Note!
• Make sure that, when the motor control with speed feedback is in use, the maximum
input frequency of 10 kHz is not exceeded.  Using DI1 and DI2 as frequency inputs
( 266)
• As the slip is calculated in the feedback V/f operation and injected through the slip
regulator, the slip compensation ( C00021 ) is deactivated with V/f control.