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Lenze · 8400 HighLine · Reference manual · DMS 12.0 EN · 06/2017 · TD23
281
5
Motor control (MCTRL)
5.11
Encoder/feedback system
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5.11.2
Generation of the actual speed value
...depending on the encoder selection and mounting direction:
Up to and including version 11.xx.xx the following applies:
• For motor control types without speed feedback (
= "0: No encoder") a speed-
proportional unit is taken for calculating the
nMotorSpeedAct_v
speed signal. This derivation,
however, is very imprecise so that in case of applications with synchronous motors without
speed feedback it is not possible to calculate the current position from the current
nMotorSpeedAct_v
speed signal.
• If no position encoder is available (
= "0: No encoder"), the
dnMotorPosAct_p
position
signal is always derived from the
nSpeedSetValue_a
speed setpoint. This derivation, however, is
very imprecise since in this case, speed limitations (e.g. by overcurrent limitations) are not
considered.
From version 12.00.00 the following applies:
• For applications with synchronous motors without speed feedback, an
nMotorSpeedAct_v
error-
free speed signal is available. This is calculated from the electrical output angle considering the
number of pole pairs of the
nMotorSpeedAct_v
speed signal.
• When synchronous or reluctance motors without feedback are used in the motor control types
V/f characteristic control (VFCplus)
Sensorless control for synchronous motors (SLPSM)
, the
nMotorSpeedAct_v
speed signal can be used to create an error-free position signal via a control
if the
nMotorSpeedAct_v
signal is read out by the control in a 1 ms cycle.
• If no position encoder is available (
= "0: No encoder"), the
dnMotorPosAct_p
position
signal is continued to be derived from the
nSpeedSetValue_a
speed setpoint. The extended
selection text "0: No encoder:nSpeedSetValue_a" in
refers to this behaviour.
• The new selection "10: No encoder: C495 or nMotorSpeedSetAct_v" in
is used to
calculate the
dnMotorPosAct_p
position signal either from the set speed feedback (when
> 0) or from the
nMotorSpeedAct_v
= 0).
• For all motor control types without speed feedback, this selection serves to improve the
creation of the
dnMotorPosAct_p
position signal.
• When synchronous or reluctance motors without feedback are used, the
dnMotorPosAct_p
position signal can be created correctly.
• In case of the motor control types with speed feedback, the
dnMotorPosAct_p
position signal
is directly created from the speed feedback signal.
Speed sensor
(
)
Position encoder
Motor mounting
direction
Direction of rotation
of motor shaft
(at setpoint = Cw)
Actual speed value
(nAct_v)
not inverted
Cw
Δ
SetPos
inverted
Ccw
not inverted
Cw
inverted
Ccw
not inverted
Cw
inverted
Ccw
not inverted
Cw
Δ
ActPos
inverted
Ccw
no encoder
Encoder set