Chapter 7 Positioning Function; Overview - Mitsubishi Electric MELSEC-L02SCPU User Manual

CHAPTER 7
7.1

Overview

(1) Definition
This function is used to move a table, machining target, tool, or other moving body (workpiece) at a specified
speed with the purpose of stopping it accurately at a target position.
(2) Features
The positioning function is controlled by dedicated instructions.
Programming tool
(a) 2-axis control
Two drive units (two motors) can be connected and two coordinates can be controlled independently or
simultaneously.
(b) OPR (Original point return)
Six types of OPR methods are available. A near-point dog (OP sensor) can be used to establish the OP
(position that becomes the starting point of each control) and "address" of this position. (Machine OPR) OPR
can also be performed automatically within the range defined by the upper and lower limit switches. (OPR retry
function)
(c) Target position and speed
• The workpiece can be moved to the target position based on a specified address or movement amount.
(Position control)
• The workpiece can be moved until a stop instruction is executed. (Speed control)
• The current position can be changed to a specified value. (Current value change function)
• The target position can be changed while the workpiece is moving. (Target position change function)
• The speed can be changed while the workpiece is moving. (Speed change function)
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POSITIONING FUNCTION
LCPU
Drive unit
Motor power
cable
Encoder cable
Drive unit
Motor power
cable
Encoder cable
Mechanical system
Hardware stroke Hardware stroke
lower limit switch upper limit switch
Near-point
watchdog Workpiece
Servo motor
Hardware stroke Hardware stroke
lower limit switch upper limit switch
Near-point
watchdog Workpiece
Servo motor