Revision February, 2017     12-1 
Chapter 12 Absolute System 
Introduction 
Delta’s absolute system includes an ASDA-A2 series servo drive, an ECMA series servo motor 
with an absolute encoder and a backup battery box for an absolute encoder. An ECMA series 
servo motor with an absolute encoder has an encoder which is able to rotate and tell the servo 
motor the actual position when the power is turned on. An absolute encoder in an ECMA series 
servo motor will constantly record the actual positions by its built-in coordinate system at any time. 
So the real position of the servo motor will be measured and recorded even if the motor shaft 
rotates after the power is turned off.  
 
An ECMA series servo motor with an absolute encoder is essential and must be connected with an 
ASDA-A2 series servo drive for a Delta’s absolute system. When an ECMA series servo motor with 
an incremental encoder is connected to an ASDA-A2 series servo drive, if the users enable the 
servo parameters for absolute system, a fault code, AL069 will be shown on the drive’s LCD 
display to alert that an error occurs. When AL069 is displayed, please examine if the connected 
servo motor is a servo motor with an absolute encoder.  While using absolute motor, as soon as it 
applies to the power, the motor speed cannot lower than 250rpm. When operating in battery mode, 
make sure the maximum speed does not exceed 200rpm. The model name of a servo motor with 
an absolute encoder is shown as below 
 
 
One servo drive uses one single battery box. Two servo drives can share a dual battery box. We 
recommend the users to choose Delta’s backup battery boxes and Delta’s encoder connection 
cables for Delta’s absolute systems for wiring and connection. Please perform the installation in 
order as specified in the quick start and user manual when connecting to an absolute system. 
Regarding the descriptions and specifications of battery boxes and corresponding accessories, 
please refer to the contents in the following sections.