Mitsubishi Electric MELSEC FX Series - Positioning Method Type; Speed Control

The Basics of Positioning Control Positioning method type
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MITSUBISHI ELECTRIC
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.)
120080da.eps
Fig. 1-8: Schematic drawing – Limit switch method
B IM
INV
Moving part
Ball screw
Limit switch for
changeover to
low speed
Limit switch for
stop
0 to 10 V DC
Inverter
Brake
Inductive motor
High speed
Low speed
Movement distance