Absolute Position Detection System - Mitsubishi Electric MELSERVO-J5 User Manual

12.7

Absolute position detection system

Structure
An absolute type linear encoder is required to configure an absolute position detection system under fully closed loop control
using a linear encoder.
In this case, an encoder battery need not be installed to the servo amplifier.
When a battery backup type rotary encoder is used, an absolute position detection system can be configured by installing the
encoder battery to the servo amplifier.
When a batteryless rotary encoder is used, the encoder battery need not be mounted to the servo amplifier.
• Use an absolute position type encoder for the load-side encoder.
Using an incremental type encoder triggers [AL. 037 Parameter error].
• When using the Mitsubishi Electric direct drive motor for the load-side encoder, the Z-phase must be passed
through before homing.
• Switching between semi closed loop control and fully closed loop control cannot be performed. Set [Pr.
PE01.0 Fully closed loop function selection] to "0" (Always enabled).
If [Pr. PE01.0 Fully closed loop function selection] is set to "1" (switching by fully closed loop selection
command from the controller and by input device CLD), [AL. 037 Parameter error] occurs.
• Use the encoder within the range of 32-bit absolute position data.
• When a linear encoder is used for the load-side encoder, absolute position-related alarms ([AL. 025
Absolute position erased]) and warnings ([AL. 092 Battery cable disconnection warning] and [AL. 09F
Battery warning]) are not detected.
Precautions
When the absolute position detection system is configured with a rotary encoder, the battery life will be shorten because the
current consumption is increased as the power from the battery is supplied to both the servo motor-side and the load-side
encoder.
12 USING A FULLY CLOSED LOOP SYSTEM
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12.7 Absolute position detection system