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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.

undefinedFAQ 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.

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)

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

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

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:

undefinedCaribou Board
undefinedFalconEye motor control reference design
undefinedIndustrial Networking Kit
undefinedTexas Instruments

Stages of implementation and associated aids

Etapa 1

Realización de capas físicas 

Las especificaciones EnDat dan una exacta descripción del timing y “bits and bytes.” Las especificaciones EnDat le ayudarán en la realización completa de la implentación. La empresa MAZeT ofrece la macro de programación FPGA, el cual cubre completamente la realización de las capas físicas. HEIDENHAIN ha chequeado esta FPGA y la recomienda para la implementación del interfaz EnDat. El empleo de la macro de programación reduce los tiempos de desarrollo (y por lo tanto tiempos de salida al mercado) además de asegurarse estar libre de posibles errores de comunicación. También reduce los tiempos de prueba y ensayo. Para más información visite www.mazet.de/produkte/sensorinterface_ics/endat/de  

Etapa 2

Comunicación basada en los "comandos de modo"  

La comunicación entre el control NC y el sistema de medida con EnDat esta basada en la transmisión de comandos. En una segunda etapa de implementación, los "comandos de modo" son empleados como comunicación básica con el sistema de medida. HEIDENHAIN ofrece un kit de demostración consistente de una tarjeta PCI, un encoder rotativo, cables y software. El software suministrado hace posible la transmisión de comandos individuales al encoder.

El cliente puede simplemente realizar un programa de aplicación (a bajo nivel) para verificar los "comandos de modo" conjuntamente con el programa macro. La comunicación esta basada en un simple acceso a registros.

Etapa 3

Realización de procesos complejos, por ejemplo accesos a memoria  

La tercera etapa de la implementación requiere procesos que comprenden la transmisión de multiples "comandos de modo". Estos procesos incluyen tareas más complejas como el acceso a memoria. El anexo de las especificaciones EnDat incluye diagramas de flujo que explican los pasos necesarios en detalle. Los mismos procesos son disponibles como ejemplos de programa en lenguaje "C" para la macro de MAZeT. 

Etapa 4

Integración de la comunicación EnDat en una estructura de control  

En la última etapa de implementación, los procesos deben ser integrados en la estructura del controlador, teniendo en consideración los diversos perfiles de encoders (absoluto, incremental, lineal, rotativo, etc.).