Advanced Topics
Commutation with Absolute Encoders
mutation information.
6.1.6 Signals and States
Beside the parameters used to configure phasing different commands and signals are provided to ana-
lyze and debug the phasing sequence.
Axes[].Commands.Commutation.Command
: This register can be used to control the phasing state and to
save the commutation angle to the encoder (if supported by the encoder
).
Invalidate
: Sets the commutation state to
Invalid
which forces a phasing sequence (if specified)
when the axis is enabled next time.
StartPhasing
: Starts a phasing sequence as specified by the commutation parameters.
StartPhasing
can be executed whether the axis is enabled or disabled. After a successful phasing, the commuta-
tion offset is written to the register
Axes[].Signals.Commutation.OffsetAngle,
the commutation state
is set Valid and the axis state will return to the state before the phasing.
StartPhasingAndSaveEncoder
: Same as
StartPhasing
but additionally the commutation offset is
saved persistent to the encoder. If
EnablingMethod
is set to
AbsoluteEncoderOffsetEncoder
this off-
set will be used for the commutation after a power cycle of the drive.
StartPhasingAndZeroEncoder
: Same as
StartPhasing
but additionally the zero of the absolute en-
coder is set equal to the zero of the commutation angle. This will cause a shift of the position. In
case the zero of the encoder is equal to the zero of the commutation angle it is possible to set the
parameter
Commutation.EnablingMethod
to
AbsolutEncoder
.
InvalidateEncoder
: This command marks the commutation offset saved on the encoder as invalid.
After a power cycle of the drive, the commutation state will be Invalid.
Axes[].Signals.Commutation.State
: This register displays the current phasing state.
Disabled
: The motor type and angle search method chosen do not require angle search (e.g. DC-
motor).
Invalid
: A valid commutation angle is not yet set. This will force a phasing when the axis is enabled
next time.
Phasing
: The phasing sequence is ongoing.
Hold
: The phasing is frozen to allow saving of the commutation offset to the encoder.
Valid
: Any phasing was successful
or the commutation offset was successfully derived from an abso-
lute encoder depending on the EnablingMethod parameter. In both cases
the commutation offset is
written to the register
Axes[].Signals.Commutation.OffsetAngle.
Axes[].Signals.Commutation.Angle
: The commutation angle describes the magnetic field of the rotor rel-
ative to the stator-coils (Figure 66). The commutation angle runs from -pπ to pπ, where p is the number
of pole pairs.
12 Endat; BissB; Tamagawa; Nikon
ServoDrive-SetupGuide_EP018
2022-08-25
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