Yaskawa MP940 - Manual (Page 316)

Absolute Position Detection
7.1.1 Description of the Function
7-2
7.1 Structure of the Absolute Position Detection Function
This section describes the Absolute Position Detection Function in the MP940.
7.1.1 Description of the Function
The Absolute Position Detection Function detects the position of the machine even if power
is turned OFF. This allows it to set the machine coordinate system automatically and to
begin operating automatically without having to return to the zero point after power is turned
ON.
The following are features of the absolute position detection system.
One of the following operating systems can be selected from parameter settings with this
function.
7.1.2 Structure of Absolute Position Detection
„ Basic Terminology
The following explanation for basic terminology used in this chapter is provided to ensure
basic understanding.
Absolute Encoder
Absolute position detection is generally performed in a semi-closed loop using an absolute
encoder built into a servomotor. The detector is comprised of an encoder that is used to
detect absolute position within one rotation and a counter that is used to count the number of
rotations.
• Eliminates the need to return to the zero point after power is turned ON.
• Enables the Software Limit Function immediately after power is turned ON.
• Eliminates the need for a zero point dog and overtravel limit switch.
• Incremental detection system using an incremental encoder.
• Absolute position detection system using an absolute encoder.
• Incremental position detection system using an absolute encoder.