Chapter 7 Absolute Position Detection System; Outline; Characteristics; Restrictions [G] [Wg] - Mitsubishi Electric MELSERVO-J5 User Manual

7
ABSOLUTE POSITION DETECTION SYSTEM

Precautions

• If [AL. 025 Absolute position erased] or [AL. 0E3 Absolute position counter warning] occurs, execute homing again.
• For the replacement procedure of the battery, refer to the following.
Page 430 Battery
• Disconnection of the encoder cable or replacement of the battery while the control circuit power supply is off causes the
encoder to erase the absolute position data. If the absolute position data is erased, execute home position setting before
operation.
• When the battery is used out of specification, the absolute position data may be erased.
7.1

Outline

Characteristics

The encoder consists of a circuit designed to detect a position within one revolution and the number of revolutions.
The absolute position detection system always detects and memorize the absolute position of the machine, regardless of
whether the controller power is on/off. Therefore, once homing is performed at the time of machine installation, homing is not
needed when power is switched on thereafter.
Even if a power failure or a malfunction occurs, the system can be easily restored.

Restrictions [G] [WG]

The absolute position detection system cannot be configured in the following conditions.
• When an incremental type encoder is being used
• Stroke-less coordinate system for infinite positioning and the like in combination with a controller other than a Mitsubishi
Electric motion module

Restrictions [A]

The absolute position detection system cannot be configured in the following conditions.
• When an incremental type encoder is being used
• Speed control mode and torque control mode
• Infinite long positioning and the like, stroke-less coordinate system
• Changing electronic gear after homing
The absolute position detection system by DIO cannot be configured in the following conditions.
• Control switching mode (position/speed, speed/torque, and torque/position)
The test operation cannot be performed in the absolute position detection system by DIO. To perform the test operation,
select incremental system in [Pr. PA03].
Precautions
Even when using a servo motor with battery-less absolute position encoder, absolute position data is erased under the
following conditions. If the absolute position data is erased, perform homing again.
• A servo motor or servo amplifier is replaced.
• The incremental system is enabled.
• [Pr. PA01 Operation mode selection] is changed.
When a servo motor other than the one that was connected at the startup of the absolute position detection system is
connected, [AL. 01A Servo motor combination error] occurs. In such cases, reconnect the servo motor that was connected at
the startup of the absolute position detection system to operate without losing the absolute position data. When replacing a
servo motor, refer to the following.
Page 292 Procedure of replacing a servo motor with battery-less absolute position encoder
7 ABSOLUTE POSITION DETECTION SYSTEM
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7.1 Outline