4 object structure, 1 object dictionary structure – INFICON SKY CDGxxxD (EtherCAT) User Manual

Page 11

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4 Object

Structure

This chapter describes the CANopen over EtherCAT (CoE) Object Dictionary.

The objects in the CoE Object Dictionary can be accessed with SDO services, and
many of the dictionary objects can be mapped for cyclic communication in PDOs.
Each object is addressed using a 16-bit index and an 8-bit subindex.

The following table presents the overall layout of the standard Object Dictionary.

Index (hex.)

Object dictionary area

1000 – 1FFF

Communication profile area

2000 – 5FFF

Manufacturer-specific profile area

6000 – 6FFF

Input area

7000 – 7FFF

Output area

8000 – 8FFF

Configuration area

9000 – 9FFF

Information area

A000 – AFFF

Diagnosis area

B000 – BFFF

Service Transfer area

C000 – EFFF

Reserved area

F000 – FFFF

Profile Specific Area Device area

Explanations for the abbreviations in the columns of the tables are given below:

Abbr.

Description

Access

SDO read/write access
• RO: object can only be read by the SDO service
• RW: object can be both read and written by the SDO service

CoE

CAN application protocol over EtherCAT

Index

Object Index (hex.) (address of an object)

NV

Nonvolatile; attribute value is maintained through power cycles

Object

Abstract representation of a particular component within a device,
which consists of data, parameters, and methods.

PDO

Process Data Object. Structure described by mapping parameters
containing one or several process data entities.

PM PDO

mapping

• Rx: object can be mapped into an Rx PDO
• Tx : object can be mapped into a Tx PDO

RxPDO

Receive PDO. A Process Data Object received by an EtherCAT slave.

SDO

Service Data Objects. CoE asynchronous mailbox communications
where all objects in the Object Dictionary can be read and written.

SI

Subindex (hex.) (sub-address of an object)

Type Data

Type

• BOOL, BIT = 1 bit. Boolean (0 = false, 1 = true)
• USINT, BYTE = 8 bit. Unsigned Byte
• UINT = 16 bit. Unsigned integer value
• UDINT = 32 bit. Unsigned integer value
• ULINT = 64 bit. Unsigned integer value
• REAL = 32 bit. Floating point
• V_STRING = 8×n bit. Visible string (1 byte for character)

TxPDO

Transmit PDO. A Process Data Object sent from an EtherCAT slave.


4.1 Object Dictionary

structure

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