Positioning Method Type; Speed Control - Mitsubishi Electric Melsec FX Series Beginners Manual

The Basics of Positioning Control
1.3

Positioning method type

In general, there are two methods to control the movement of a workpiece: speed control and
position control. For basic, more rudimentary positioning, speed control can be used with an inverter
and general purpose motor. For systems where precision is a must, servo systems are required for the
advanced handling of pulse commands.
1.3.1

Speed control

Limit switch method
Two limit switches are provided in places where a system's moving part passes. At the first limit switch,
the motor speed is reduced. At the second limit switch, the motor turns off and the brake turns on to
stop the moving part.
In this method, because position controllers are not required, the system configuration can be
realized at reasonable cost.
– Guideline of stopping precision: Approximately ±1.0 to 5.0 mm
(The stop precision shows a value in a case where the low speed is 10 to 100 mm/s.)
Fig. 1-8: Schematic drawing – Limit switch method
1 - 6
Inductive motor
Brake
B IM
Inverter
INV
0 to 10 V DC
Moving part
Ball screw
High speed
Low speed
Movement distance
Positioning method type
Limit switch for
changeover to
low speed
Limit switch for
stop
120080da.eps
MITSUBISHI ELECTRIC