User guide

Page 43
ServoTube 25/38 module User Guide
Appendices
FEEDBACK
The ServoTube Module is available with three feedback options with option S supplied as standard.
Option S feedback outputs analogue, differential sine and cosine signals for providing position feedback. Shown
below are the relationships between forcer phase back EMF and position sensor outputs for one direction of
motion (as shown by arrows). It should be noted that +SIN or -SIN is always in phase with forcer phase U. For the
motion shown, -SIN is in phase with forcer phase U. For motion in the opposing direction +SIN is in phase with
forcer phase U.
0 30 60 90 120 150 180 210 240 270 300 330 360
electrical degrees
+2.75V
+2.50V
+2.75V
+2.25V
+2.50V
+2.25V
Neutral
-SIN +SIN
-COS
+COS
Phase U Phase V Phase
W
Back EMF
(phase to neutral)
Sensor signals