PAS 62408:2005 pdf download Real-time Ethernet Powerlink (EPL)
The Object Dictionary may contain a maximum of 65536 entries which are addressed through a 16-bitindex.
The Static Data Types at indices 0001, through 001F, contain type definitions for standard data typeslike BOOLEAN,INTEGER, floating point, string, etc. These entries are included for reference only;they cannot be read or written.
Complex Data Types at indices 0020, through 003F, are pre-defined structures that are composed ofstandard data types and are common to all devices.Manufacturer Specific Complex Data Types at indices 0040, through 005F, are structures composedof standard data types but are specific to a particular device.Device Profiles may define additional data types specific to their device type. The static data typesdefined by the device profile are listed at indices 0060, – 007F, the complex data types at indices0080-009Fh
A device may optionally provide the structure of the supported complex data types (indices 0020,005F, and 0080 009F) at read access to the corresponding index, Sub-index 0 provides thenumber of entries at this index, and the following sub-indices contain the data type encoded asUNSIGNED16 according to 6.1.4.4.
EPL Specific Static Data Types shall be described at indices 0400, – 041F, These entries areincluded for reference only; they cannot be read or written. EPL Specific Complex Data Types shall bedescribed at indices 0420, – 04FF
The Communication Profile Area at indices 1000, through 1FFF, contains the communication specificparameters for the EPL network. These entries are common to all devices.The standardised device profile area at indices 6000, through 9FFF, contains all data obiects commonto a class of devices that can be read or written via the network. The device profiles may use entriesfrom 6000, to 9FFF, to describe the device parameters and the device functionality. Within this rangeup to 8 diferent devices can be described. in such a case the devices are denominated MultipleDevice Modules. Multiple Device Modules are composed of up to 8 device profile segments. In thisway it is possible to build devices with multiple functionality. The different device profile entries areindexed at increments of 800n.
For Multiple Device Modules the object range 6000 h to 67FF h is sub-divided as follows:
• 6000 h to 67FF h device 0
• 6800 h to 6FFF h device 1
• 7000 h to 77FF h device 2
• 7800 h to 7FFF h device 3
• 8000 h to 87FF h device 4
• 8800 h to 8FFF h device 5
• 9000 h to 97FF h device 6
• 9800 h to 9FFF h device 7
The PDO distribution shall be used for every segment of a Multiple Device Module with an offset of64., e.q. the first PDO of the second segment gets the number 65.. In this way a system with amaximum of 8 segments is supported.
The Object Dictionary concept caters for optional device features: a manufacturer does not have toprovide certain extended functionality on his devices but if he wishes to do so he must do it in a predefined fashion.
Space is left in the Object Dictionary at indices 2000, through 5FFF, for truly manufacturer-specificfunctionality.
2.2.2.1 Index and Sub-Index Usage
A 16-bit index is used to address all entries within the Object Dictionary. ln the case of a simplevariable the index references the value of this variable directly. ln the case of records and arrays.however, the index addresses the whole data structure.To allow individual elements of structures of data to be accessed via the network a sub-index isdefined. For single Object Dictionary entries such as an UNSIGNED8, BOOLEAN,INTEGER32 etcthe value for the sub-index is always zero. For complex Object Dictionary entries such as arrays orrecords with multiple data fields the sub-index references fields within a data-structure pointed to bythe main index The fields accessed by the sub-index can be of differing data types.
2.3 Communication Model
The communication model specifies the different communication objects and services and theavailable modes of frame transmission triggering.The communication model only specifies the EPL-specific communication objects of the EPL Modeand Basic Ethernet Mode. (4.2 resp. 4.3). The mechanism for Standard Ethernet communicationin inBasic Ethernet mode is not within the scope of this specification.The communication model supports the transmission of isochronous and asynchronous framessochronous frames are supported in EPL Protected Mode only, asynchronous frames in EPLProtected Mode and Basic Ethernet Mode.