Endat2.X Bidirectional Interface; Encoder Analog Output - Servotronix CDHD2S User Manual

Application Setup
BISSCINFO

6.5.5 EnDat2.x bidirectional interface

The EnDat interface is a digital bidirectional interface for encoders. This interface can not only
transmit the position values of the incremental and absolute encoders, but also transmit or update
the data stored in the encoders or save new information. The data is transmitted synchronously via
the clock signal of the subsequent electronic device. The data type (e.g. position value, parameters,
diagnostics) is selected by the mode command sent by the subsequent electronics to the encoder.
CDHD2S supports EnDat2.1 communication protocol, which is a subset of EnDat2.2 protocol.
All EnDat2.2 enabled devices support the 2.1 protocol, including commands and queries related to
CDHD2S; therefore, all EnDat2.2 enabled devices can be used with CDHD2S.
EnDat2.x can be used with CDHD2S in the following ways:
EnDat2.x communication only: Suitable for the setting that the drive only depends on
⚫
the serial data provided by the feedback device (position information source).
EnDat2.x with Sine/Cosine: Suitable for the following settings (a) the drive performs
⚫
encoder initialization and uses serial data for position initialization; (b) position
update during operation is derived from the sine/cosine signal.
Note: CDHD2S does not support querying and setting parameters during position feedback
operation.
The CDHD2S communication rate is 2MHz (to modify the communication rate, please refer to
VarComFEEDBACKBR).
EnDat2.x encoder with sine signals: The position feedback (PFB) value is calculated from the
HWPOS value and sine/cosine signals during EnDat initialization after power-on and after clearing
feedback-related faults. It may take several seconds for initialization to complete. During this time,
the position feedback (PFB) value is undefined and therefore the drive cannot be enabled.
EnDat encoder initialization takes approximately 2.5 seconds; during this process, if the drive
status is interrogated (using the ST command), the message "ENDAT initialization not completed"
will be displayed.
The EnDat encoder +5V DC supply must be switched off during (re)initialization. During EnDat
initialization, CDHD2S turns off the DC voltage +5V provided to the encoder. However, if the
encoder receives DC voltage +5V from a different source and is not switched off, initialization may
fail.

6.5.6 Encoder analog output

The encoder analog output, also known as equivalent encoder output (EEO) or buffer encoder
output, is available at the controller interface (C2).
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