The Fundamentals Of Motion Control - Siemens SIMOTION C230-2 Equipment Manual

The Fundamentals of Motion Control

Position-controlled motion control for servo axes (onboard I/Os)
The C230-2 allows the position-controlled motion control of up to four axes. The
C230-2 provides an analog output for the speed setpoint for each axis and an
encoder input for the cyclic sensing of the actual position value.
C230-2
DAC
+
Position
controller
–
Fig. 2-1 Servo system with converter, e.g. SIMODRIVE 611 analog, with external incremental encoder
Incremental encoder
Encoders are generally connected for position measurement. These supply
counting pulses, according to their resolution, for the incremental distance
travelled. They can be either rotary or linear.
A "homing" (referencing) operation must be performed in order to determine the
absolute position reference.
Absolute encoder (SSI)
Instead of conventional incremental encoders, which supply only one dimension for
the distance travelled, absolute encoders with a serial interface can be connected.
No homing operation need be performed for these encoders as they always supply
the absolute position as an actual value.
A one-off adjustment of the absolute encoder is required when the machine is ini-
tially commissioned.
E Siemens AG, 2003 All rights reserved
SIMOTION C230-2, 04.2003 Edition
Converter
Speed
Power section
setpoint
X2
Current controller
Speed controller
Enable
X3
Actual position value, zero mark
X4
X5
X6
X1
Servo motor
M
3
Actual speed value
2
Encoder
2-17