5.2 Absolute Encoders
5.2.2 Absolute Encoder System Startup
5-18
5.2.2
Absolute Encoder System Startup
An absolute encoder system is a system that uses an absolute encoder.
With an absolute encoder system, the origin must be set during the initial setup procedure
when the system is commissioned. There are two origins, the absolute encoder’s origin and the
machine’s origin. These are called the origin of the encoder coordinate system and the origin of
the machine coordinate system.
The absolute encoder system establishes the positional relationship between the origin of the
machine coordinate system and the origin of the absolute encoder.
When the origin is established, positions are then managed based on the origin of the machine
coordinate system. This reference position will not change even if the power supply is turned
OFF. Therefore, it is not necessary to return to the origin after turning ON the power supply.
The following table gives the setup procedure for an absolute encoder system.
The following pages give detailed explanations of setting up the absolute encoder, setting the
origin of the machine coordinate system, and the current value of the machine coordinate sys-
tem.
Setting Up the Absolute Encoder (Initialization)
The multiturn data for the absolute encoder system must be initialized the first time the system
is started. When the absolute encoder is set up (initialized), the multiturn data is initialized and
any alarms related to the absolute encoder are reset.
Absolute encoder setup (initialization) is required in the following situations.
• When the system is first started
• When an Encoder Backup Alarm (A.810) occurs
• When an Encoder Checksum Alarm (A.820) occurs
• When you want to reset the multiturn data in the absolute encoder
Refer to the following section for information on how to reset an absolute encoder.
5.2.3 Resetting the Absolute Encoder on page 5-20
Step Item Description
1
Confirming the Machine Config-
uration and Wiring
Confirm that the components and cable connections are correct.
2
Setting Up the Absolute
Encoder (Initialization)
The absolute encoder is initialized to initialize the multiturn data.
Setting Up the Absolute Encoder (Initialization) on page 5-18
3
Setting Parameters Related to
Absolute Position Detection
There are two types of machine operation. One type is finite-length
operation, where round-trip operation is performed within a defined
travel interval, and the other type is infinite-length operation, where
movement is performed in one direction, such as for a conveyor
belt. Set the related parameters according to the operation
method.
Finite-length Operation on page 5-26-Parameter Settings on page
5-26
Infinite-length Operation with Simple Absolute Infinite Axis Position
Management on page 5-32-Parameter Settings on page 5-32
Infinite-length Operation with Non-simple Absolute Infinite Axis
Position Management on page 5-36-Parameter Settings on page 5-
36
4
Setting the Origin of the
Machine Coordinate System
–
The position data of the absolute encoder is the position coordinate from the origin of the
absolute encoder.
The absolute encoder position data consists of the following two types of information.
• The amount of rotation from the origin of the encoder coordinate system (multiturn data)
• Position within one rotation (number of pulses): Initial incremental pulses
The following formula is used to calculate the absolute encoder position data.
Absolute encoder position data = Multiturn data × Number of encoder pulses per rotation +
Position within one rotation (number of pulses)
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