Tolomatic User Guide:
IMA-S Integrated Motor Rod-Style Actuator - Stainless Steel
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E L E C T R I C A L I N S T A L L A T I O N G U I D E L I N E S
Absolute Encoder Feedback
The standard commutation offset for the absolute encoders offered in the IMA-S is set at 0 electrical
degrees. This is accomplished by first locking the motor rotor with a current vector from phase
U (+) to phase V and W (-), and then sending a set-zero position command to the encoder using
appropriate programming tool.
Digital Incremental Encoder Feedback
The incremental quadrature encoder utilizes differential A and B signals for tracking position and
differential index pulse and halls for commutation. The standard commutation offset of the index
pulse for the incremental encoder offered in the IMA-S is set at 30 electrical degrees. This is
accomplished by first locking the motor rotor with a current vector from phase U (+) to phase W (-),
and then using an index alignment tool to establish commutation. This provides manufacturing the
simplest means for aligning a feedback device, however, some manufactures will reference a motors
back emf when discussing commutation angles. The following graph shows the index pulse location
in reference to the motors back emf.
0
30
60
90
120
150
180
210
240
270
300
330
360
Back EMF Voltage vs Electrical Angle
U
V
W
Figure 5-2: Back EMF Voltage vs Electrical Angle
This provides manufacturing the simplest means for aligning a feedback device, however, some
manufactures will reference a motors back emf when discussing commutation angles. The following
graph shows the index pulse location in reference to the motors back emf.
0
30
60
90
120
150
180
210
240
270
300
330
360
Back EMF Voltage Phase to Phase vs Electrical Angle
V
→
W
W
→
U
U
→
V
Figure 5-3: Back EMF Voltage Phase to Phase vs Electrical Angle
The quadrature output of the encoder will be such that the rising edge of the A channel leads the
rising edge of the B channel with positive rotation as defined in the graph above.
