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Ndrive HL User’s Manual
4-26 www.aerotech.com
4.4.1.2.
Configuring the Analog Feedback Signals
Using the Encoder Feedback Configuration Utility to set up a
resolver/inductosyn
The RDP option of the Ndrive HL can be optimally aligned quickly, using the Encoder
Feedback Configuration utility within the NScope.exe utility.
When the Ndrive HL is configured for Resolver Feedback (via the CfgFbkPosType axis
parameter), then the currently selected channel (1 or 2, defined via the CfgFbkPosChan
axis parameter) of the RDP board will output its analog inputs for SIN/COS into the
analog input channels of the Encoder Configuration Feedback utility (a utility also used
to configure the -MXH option). The values sampled by the analog inputs reflect the peak
value of the carrier-frequency sine waves used by the Resolver to Digital converter.
The Position feedback type, at present, dictates which
analog channels are sampled.
There are two axis parameters, which are used to configure the analog feedback from a
resolver or inductosyn for optimum performance:
•
CfgFbkRDGain defines the peak amplitude of the reference sine wave to the
resolver.
•
CfgFbkRDCosPhase defines the phase delay on the Cosine phase of the dual-
phase oscillator.
When to use the CfgFbkRDCosPhase axis Parameter:
The Cosine reference signal can be adjusted from approximately 0 degrees (i.e. in phase
with the SINE reference signal) to 180 degrees, with a nominal value of 90 degrees. This
axis parameter is primarily for use with inductosyns, which have a nominal phase shift
from the reference signal of 90 degrees. This value may vary from system to system, and
therefore can be adjusted to ensure that the alignment of the feedback signals to the
reference signal is at its optimum, for better performance.
This signal can also be used to adjust for resolvers that have a large amount of phase lag.
Typically, less than 5 degrees of phase lag is acceptable and does not require use of the
COS reference.
Use of this axis parameter requires that the jumper on the
RDP board for this channel (JP1 for channel 1 or JP2 for
channel 2) be set from 2-3 instead of from 1-2. Also, in
order for the A/D’s to sample properly, the appropriate bit
in the CfgFbkRDConfig axis parameter should be set to 1
(bit 0 for channel 1 or bit 1 for channel 2).
For most resolvers, use of the CfgFbkRDCosPhase axis parameter is not required. If this
axis parameter is not being used, the jumpers should be set to 1-2 and the bits in the
CfgFbkRDConfig axis parameter should be set to 0. Skip to the section on adjusting the
R/D Gain.
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