Implementation of EnDat

The EnDat interface is typically implemented in four stages:

  • Realization of the “physical layer”; i.e. timing, “bits and bytes,” etc.
  • Communication on the basis of mode commands 
  • Realization of complex processes, for example memory access 
  • Integration of EnDat communication in the controller structure under consideration of the various encoder profiles (absolute, incremental, linear, rotational, …)

HEIDENHAIN provides various aids for the individual implementation stages:

  • Documentation
  • EnDat demotool software
  • EnDat master

In the following you will find an overview of these aids and how they are used in the individual stages of implementation.

Documentation:

EnDat Technical Information:
The Technical Information provides a first overview of the EnDat performance. It summarizes the essential features of EnDat concisely.

Overview of EnDat documents

Overview of EnDat documents:

FAQ:
The FAQ area lists all information that we frequently discussed with our customers in the past.

FAQ area

EnDat Specifications:
The EnDat specifications contain detailed information on the physical interface, the timing and the data contents that are transmitted. This information is required for the implementation of the EnDat interface in subsequent electronics. For more information, please refer to your contact person at HEIDENHAIN.

Application Notes: 
Contain supplementary information on the specifications regarding the following topics: 

  • Structuring of mode command sequences 
  • Online diagnostics 
  • Zero point shift 
  • Handling of incremental encoders 
  • Implementation example 
  • Implementation of mode commands 
  • Implementation test

EnDat Seminar:
The EnDat seminar provides detailed information about the different aspects of the EnDat interface:

  • EnDat specifications
  • Information on cables and connecting elements
  • Information about the EnDat master
  • Practical exercise in communication with EnDat encoders via mode commands
  • Information on online diagnostics, datum shift, ...

The topics stated above are discussed using the "EnDat 2.2 Workbook", which provides compact information on all topics (including the EnDat specifications).

For more information, please refer to your contact person at HEIDENHAIN.

For more information, please refer to your contact person at HEIDENHAIN.

For more information, please refer to your contact person at HEIDENHAIN.

EnDat Demotool software:
Communication between the encoder and the subsequent electronics via the EnDat interface is based on mode commands that the subsequent electronics send to the encoder. The mode commands determine what data content is to be transmitted, such as position value, parameters, diagnostics, ...
The Demotool software runs on the PWM 20 and the IK 215, and permits easy communication with the encoder based on the mode commands:

  • Display of the returned values of the encoder (position and additional data)
  • Entry of the parameters to be transmitted to the encoder for each mode command
  • Display of communication error conditions
  • Adjustment of the transmission frequency
  • Communication is recorded on a log page for analysis later
  • EnDat 2.1 and EnDat 2.2 mode commands are supported

These features support the design process in the following way:

  • First, communication via mode commands can be tested outside the control loop
  • It can be used as a reference in the course of integration of the EnDat master into the control loop
  • Service for encoders together with the ATS software and the PWM 20 (or the IK 215)

EnDat Master:
The EnDat master communicates with EnDat encoders from HEIDENHAIN. This allows simple transmission of position data and additional information to the superior application. The EnDat master can be integrated by means of a micro controller (µC) or an FPGA (Field Programmable Gate Array) or ASIC.

The µC solutions are used if the intended clock frequencies are relatively low. For µC integration, HEIDENHAIN offers an example code for the implementation of the EnDat 2.1 mode commands; for more information, please refer to your contact person at HEIDENHAIN.

Integration in an FPGA or ASIC is selected primarily for high transmission frequencies with purely serial data transfer. Different variants are available for integration in an FPGA or ASIC; the following graphic shows the block diagram for the EnDat master variants:

  • EnDat Master Standard
  • EnDat Master Reduced (only EnDat Protocol Machine)
  • EnDat Master Light (only EnDat Protocol Machine)

EnDat Master Standard:
Due to the purely serial data transfer, an FPGA or ASIC is sufficient as master for the implementation of the EnDat 2.2 interface in subsequent electronics. To simplify the integration of the EnDat master in subsequent electronics, MAZeT (www.mazet.de) developed an EnDat master soft macro (EnDat Master Standard) with the following features:

  • Encapsulated code block tested by HEIDENHAIN
  • The implementation of the code block is secured through test vectors
  • Designed for a short time to market
  • All EnDat encoders from HEIDENHAIN are supported

More information and documentation can be obtained from MAZeT:

  • EnDat master soft macro information sheet (insert link)
  • EnDat master soft macro documentation
  • EnDat master soft macro software examples

For more information, please contact MAZeT(www.mazet.de)

EnDat Master Reduced:

  • Only the pure EnDat functionality (EnDat Protocol Machine) is integrated
  • All EnDat encoders from HEIDENHAIN are supported
  • Time to market unfavorable in comparison with the EnDat master standard version, as extended tests are required
  • It does not offer further support regarding the convenient handling of the code or a micro controller interface
  • Due to the restricted functionality, the code size is smaller than of the EnDat master standard version
  • The code was tested only in an example application
  • A concise documenation is available

For more information on applications of the EnDat master reduced version, please refer to your contact person at HEIDENHAIN.

 EnDat Master Light:

  • VHDL example code that only covers part of the EnDat functions
  • Supports only absolute EnDat encoders, no incremental and battery-buffered encoders
  • Time to market unfavorable in comparison with the EnDat master standard version, as extended tests are required
  • Only the position is transferred in purely serial operation, no additional EnDat information
  • It does not offer further support regarding the convenient handling of the code or a micro controller interface
  • The code size is significantly smaller compared with the standard and reduced variants
  • T he code was tested only in an example application
  • A concise documenation is available (English only)

The EnDat Master Light can be provided at no charge as example VHDL code. Please refer to your contact persons at HEIDENHAIN.

FPGA development boards that permit implementation of the EnDat interface:

Caribou Board
FalconEye motor control reference design
Industrial Networking Kit
Texas Instruments

Stages of implementation and associated aids

Stage 1:

Realization of the physical layer

The EnDat specifications provide an exact description of timing and the “bits and bytes.” The EnDat specifications help you perform the entire implementation. MAZeT offers the FPGA soft macro, which completely covers the realization of the physical layer. HEIDENHAIN has tested the soft macro and recommends it for the implementation of the EnDat interface. The use of the EnDat soft macro reduces the developing time (time to market) and ensures error-free communication. This also minimizes the time needed for testing. For more information, visit www.mazet.de/produkte/sensorinterface_ics/endat/de.

Stage 2:

Communication on the basis of mode commands

Communication between the NC control and the EnDat encoder is based on the “mode commands.” In a second stage of implementation, the mode commands are used to set up basic communication with the encoder. HEIDENHAIN provides the demo-tool software that makes it possible to transmit individual commands to the encoder. The customer can very simply add a “low-level” application software to test the mode commands together with the EnDat master soft macro. Communication is based on simple register access.

Stage 3:

Realization of complex processes, for example memory access

The third stage of implementation then requires processes that comprise the transmission of multiple mode commands. These processes then include more complex tasks such as memory access. The annex of the EnDat specifications includes flowcharts that explain the required steps in detail. The same processes are available as example programs in “C” for the EnDat soft macro from MAZeT.

Stage 4:

Integration of EnDat communication in the controller structure

In the last stage of implementation, the processes must then be integrated into the controller structures under consideration of the various encoder profiles (absolute, incremental, linear, rotational, etc.).