Ndrive HP 10/20/30 User’s Manual
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4-29
4.4.1.3. Configuring the Commutation Initialization
The commutation of brushless motors with resolver feedback may be initialized two
ways. The first method uses the number of motor pole pairs combined with the maximum
resolution of the R/D board to determine an initial commutation position. The second
method initializes the motor normally using the Hall-effect feedback signals.
Setting the CfgMotType axis parameter to auto-MSET can
be used if the R/D auto-configuration or Hall-effect signals
cannot be used.
R/D auto-configuration typically CAN’T be used with
inductosyns as they have multiple electrical cycles per
revolution of the motor. R/D auto-configuration will ONLY
work if you have EXACTLY 1 cycle of the Sine and Cosine
signals per revolution of the motor.
The Commutation Initialization method of the R/D is specified through bit 8 of the
CfgFbkRDConfig axis parameter.
Setting this bit to 1, utilizes Hall-effect commutation initialization (i.e. commutation is
initialized similar to encoder feedback). Note that this requires proper Hall effect to back-
EMF configuration and/or proper commutation phase shift axis parameter setting; see
brushless motor setup information for more details.
Setting this bit to 0 uses the R/D auto-Configuration, when the axis is enabled.
The position feedback type dictates which channel is used
for commutation initialization. Typical configuration of the
R/D has the CfgFbkPosType axis parameter set to 6 and
CfgFbkVelType axis parameter set to 0 (use position). If
two resolvers or inductosyns are used in a dual-loop
mode, the position source will generate the commutation
initialization, but the velocity source will maintain
commutation position after enable. Dual-Loop with
resolvers and other feedback sources is not advisable.
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