Yaskawa Absolute Encoders with Apollo III

Yaskawa Absolute Encoder feature allows the Apollo III to read the encoder position without the need for homing.  When the CNC control software starts the software will read the encoder positions from the servo drives and update the internal positions from 0 to the actual motor positions.



Absolute Encoder License

Use the VSI Device Manager to confirm the Absolute Encoders feature is active. Or you need to purchase it and the software license part number is ABS-57.


Buffer board X15-03-04

This board is used to send the SEN command to the Yaskawa servo drive through the Servo Adaptor Board.  The board needs to be installed onto the Apollo III and a wire ran from the terminal labeled "1" on the green block to J1 pin "5" of the Servo Adaptor Board.


Digital Servo Adaptor board X15-02-09

This board is used to connect the Yaskawa drive to the Apollo III for commands and feedback.  Confirm the version number on the board is at least V1.08 or it will not work with the Absolute Encoder interface.



Motor Encoder Cable with Battery JZSP-CSP12-E

Yaskawa servo motors need a battery on the encoder cable to use the Absolute Encoder feature.  A new encoder cable can be purchased with the battery installed or a adaptor can be used like the one in the following photo.



Hardware Kit

  • Buffer board part number X15-03-04
  • Digital Servo Adaptor board part number X15-02-09 with jumper installed
  • Motor Encoder cable with batter or battery adaptor JZSP-CSP12-E
  • Standoff MPN number Hex6.35x17.46 and MM number 100536
Remove cover
Remove mounting screw


Install Standoff


Install Buffer Board


Reinstall mounting screw


Install jumper on servo adaptor J5 pin 2-3 next to the labeled SEN


Install wire from Buffer Board to all Yaskawa servo adaptors for SEN signal

Install Motor Encoder Cable with Battery


Software and Parameters Setup

Yaskawa Servo Drive

Servo Drive Parameters:

We need Pn002.2 set to 0 (Factory setting).  This will enable the SEN input to be used to send the encoder position to the motion controller.


Servo Drive Absolute Encoder Setup

The rotational data will be a value between -2 and +2 rotations when the absolute encoder setup is executed. The reference position of the machine system will change. Set the reference position of the host
controller to the position after setup.
If the machine is started without adjusting the position of the host controller, unexpected operation may
cause injury or damage to the machine. Take sufficient care when operating the machine.

Setting up the absolute encoder is necessary in the following cases:

  • When starting the machine for the first time
  • When an encoder backup error alarm (A.810) is generated
  • When an encoder checksum error alarm (A.820) is generated
  • When initializing the rotational serial data of the absolute encoder
Set up the absolute encoder with Fn008.
  1. Precautions on Setup
    Set up the encoder when the servo ON signal (/S-ON) is OFF.
    If the following absolute encoder alarms are displayed, cancel the alarm by using the same method as the set
    up (initializing) with Fn008. They cannot be canceled with the SERVOPACK alarm reset input signal (/
    Encoder backup error alarm (A.810)
    Encoder checksum error alarm (A.820)
    Any other alarms (A.8xx) that monitor the inside of the encoder should be canceled by turning OFF the
  2. Procedure for Setup
    Follow the steps below to setup the absolute encoder.


Read Encoder Output Pulse Parameter

If using Fully-closed Loop Control with External Absolute Encoder use 1048576 for the Encoder Counts and skip this section.

Read the number of encoder pulses per revolution in parameter Pn212.  Now we need to multiply the encoder pulses by 4 to convert them to encoder counts.


Encoder Pulses - Pn212 = 4096
Encoder Counts - 16384 = 4096 * 4

Now we can enter the calculated value into the Control parameter "Encoder Counts Per Rev Motor x" under the Absolute Encoders section.

Software Setup

Navigate to the Control Parameters and enter Absolute Encoder into the filter box.  To enable Absolute Encoders on the Control you need to change the following parameters:

  • Absolute Encoders HiCON EnabledYes

Configure the following parameters for each motor that will use Absolute Encoders

  • Absolute Encoders Enabled Motor xx = Yes
  • Encoder Counts Per Rev Motor xx = Encoder Counts calculated in the section Read Encoder Output Pulse Parameter 
  • Origin Offset Counts Motor xx = Optional, offset the absolute value read from the drive.  Units are Encoder Counts.



Restart the CNC Control software and when the software loads it should read the encoder positions from the Servo Drives and mark each axis as Homed.  When the Control software is disabled and you press "Reset" the control will update the encoder positions again.  Another option is to press Compile Scrips to read the encoder positions.

Syncing Slave Motor Positions

When using ABS encoders on a axis with multiple motors caution needs to be taken to sync the motor positions before enabling or commanding any motion.

Squaring the Axis

Manually position the motors, ball screws or pinions so the axis is square and not mechanically binding.

Reset the ABS Encoder Positions in the Drive

Repeat steps Set up the absolute encoder with Fn008 to make sure the encoder is a close to zero as possible.  When you run this function in the drive the encoder will not necessarily get set to zero. 

Check Encoder Positions

All the Encoder positions need to match all the motors mapped to the slaved axis.  To check the Encoder Positions open the HiCON status window. From the top menu select Diagnostic -> HiCON to open the HiCON Status window.


Compare the Encoder positions from all the motors mapped to the axis and find the difference between the master motor encoder and the slave motor encoder.  If the motor encoder positions match then all motors are synced and ready for motion. 


Sync Encoder Positions

Navigate to the Control Parameters and enter Absolute Encoder into the filter box.

Find the first slave motor and enter the difference between the master motor encoder counts and the slave motor encoder counts into the Origin Offset Counts Motor xx.  When the HiCON reads the encoder positions from the drive it will apply these offsets to each motor.


Now we need to repeat the Check Encoder Positions and confirm that all the positions match.  If they don't match then we might need to check the sign of the encoder counts we entered into Origin Offset Counts Motor xx. Sometimes changing the value to negative will fix this problem.


Control Parameters

Control Parameters are where many of the features and machine functions are setup.  There are many common parameters that are the same across all machine types, but each machine type can have additional parameters for machine specific settings.

Viewing and Modifying Parameters

Navigate to the Service Page -> Maintenance Page and click on Interface Config


Now you can view and edit any of the Control Parameters.  Use the Predefined Filters or enter your own search terms in the Filter box.