Motion Actuator - Manual (Page 27)

POSITION SENSOR
The position sensor outputs analogue, differential sine and cosine signals for providing position feedback. Figure C.1
shows the relationships between motor phase back EMF and position sensor outputs for one direction of motion (as
shown by arrows in Figures C.1 and C.2). It should be noted that +SIN or -SIN is always in phase with motor phase U.
For the motion shown, -SIN is in phase with motor phase U. For motion in the opposing direction +SIN is in phase with
motor phase U.
SPECIFICATION VALUE UNITS
Output signal period 71.2 mm
Signal amplitude (between +/- signals) 1 V
pk-pk
Output current ±10 mA
Supply voltage 5 ± 0.25 V d.c.
Supply current (output current =0) 15 ± 5 mA
Resolution (1) 20 mm
Position Repeatability (2) ±25 mm
Absolute Accuracy (3) ±400 mm/m
Notes
(1) Dependent on amplifier. (2) Dependent on amplifier. Under constant operating conditions. Self-heating of the thrust rod by the motor will cause
expansion in the thrust rod during the initial warm up period. In high duty applications (corresponding to an internal motor temperature of 80°C) a 1
metre thrust rod will expand typically by 250 mm. (3) Maximum error over 1metre under constant operating conditions.
ServoTube 38 Installation Guide Appendices
Page 21
Figure C.1- The relationships between motor phase back EMF and position sensor outputs
Figure C.2 - Arrows indicate direction of motion