TG - Accurax G5 Series - Error 40 "Absolute Encoder System Down"

Purpose

This guide explains how to reset Error 40 (Absolute Encoder System Down) in Omron Accurax G5 Servo Drives using Sysmac Studio. This error occurs when the absolute encoder data is cleared due to servo drive replacement or other system changes. The document outlines both manual and automatic methods for resetting the encoder and restoring normal operation.

Explanation 

Error 40 is triggered when the absolute encoder loses its stored multi-rotation data, requiring re-initialization.

This typically happens when replacing the servo drive, which clears the encoder’s absolute position data.

The objective is to reset the encoder error, restore normal motion control, and ensure accurate position tracking.

Supported devices

Requirements 

Procedure

How To Reset G5 ECT Error 40 "Absolute Encoder System Down" With Sysmac Studio

If a motor with an absolute encoder is used, the absolute value data in the absolute encoder is cleared when the Servo Drive is replaced, so needs to be setup again. The multi-rotation data will be different from before it was replaced, so initializing of the Motion Control Unit settings is required. Here are two ways to do it in Sysmac Studio.

Method 1: Resetting it manually:

Step 1: Go online with Sysmac Studio to your NJ-controller.

Step 2: Right click under Configurations and Setup ->EtherCAT on the Servo drive that has the Absolute Encoder motor connected and click Online.

Step 3: Right click again on the Servo drive and click on Absolute Encoder.

Step 4: The following warning will show:

Step 5: There are 2 buttons on the bottom of the next screen. Click first on the Multi-Turn Data and Encoder Error Clear button and then on Drive Current Error and Battery Alarm Clear button.

Step 6: After clicking on the Drive Current Error and Battery Alarm Clear button this 2 warning displays will be shown:

Step 7: Reset the Error through the Troubleshooting under Tools -> Troubleshooting

Method 2: Resetting it automatically

You can write code to reset from the program. How it is activated (automatically or through an HMI button etc) is up to the programmer. This example will reset the Servo's encoder after power on.

Step 1: Make an Inline ST with this following code:

SdoObj.Index:=16#4102; //Reset the Encoder ABS

SdoObj.Subindex:=0;

SdoObj.IsCompleteAccess:=FALSE;

WriteData:=DWORD#16#6A646165;

Step 2: Add code to call the Function Block EC_CoESDOWrite and put in the needed parameters, for example:

Step 3: Synchronize your project.

Done!

For more detailed information, refer to the Accurax G5 Series User Manual 

Date/Revision History

First review 11/09/2024 V1.0

2nd Review 01/17/2025

3rd Review 02/05/2025

Author:

Aimee Rivera, Technical Support Engineer

References

G5-series User Manual