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Ndrive HL User’s Manual
4-30 www.aerotech.com
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 at present 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 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.
Finding the Proper Commutation Offset in R/D Auto-Configuration Mode
The R/D Auto-Configuration mode assumes that the zero crossing of the R/D Converter
is aligned with the 0 angle of commutation on the Ndrive HL. Therefore, to determine
the commutation offset angle, perform the following steps:
The resolver absolute counter may also be read in the
Ndebug utility via the command sequence:
“DSPMEMREAD 2 0xEB0006” for channel 1, or 0xEB0007
for channel 2.
1)
Open the Nstat.exe utility.
2)
Select the tab, which displays the absolute resolver feedback register.
3)
Rotate the resolver until you have an approximate zero value on the feedback
register (note that this value will roll over at 65535).
4)
Begin with an MSET value of 0 degrees, execute MSET commands with an
increasing angle until you see a value of 0 indicated for the absolute resolver
angle. This MSET angle is the desired commutation offset.
5)
Enter the value from step 4 into the CfgMotOffsetAng axis parameter. Note that
for negative values, you must add 360 degrees (valid parameter range is 0-360
degrees).
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