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| Beide Seiten der vorigen RevisionVorhergehende Überarbeitung | |||
| embedded_systems:ethercatinterface:ethercatinterfaceelmo [2019-05-21 09:25] – mgehrig2 | embedded_systems:ethercatinterface:ethercatinterfaceelmo [2019-06-26 15:30] (aktuell) – gelöscht graf | ||
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| - | ====== EtherCATInterfaceElmo ===== | ||
| - | ===== Summary ===== | ||
| - | The //" | ||
| - | It consists of the following components: | ||
| - | * EtherCatInterfaceElmo.hpp | ||
| - | * EtherCatInterfaceElmo.cpp | ||
| - | * EtherCatInterfaceElmo_config.hpp | ||
| - | |||
| - | The //" | ||
| - | The low level methods (' | ||
| - | |||
| - | These low level methods read and write individual data objects to/from the stack. | ||
| - | Which objects are available and their file type must be read from the documentation of the manufacturer of the EtherCAT slave. | ||
| - | Each data object has its own method. | ||
| - | These are the only methodes which use the low level get/set methodes from //" | ||
| - | |||
| - | Where a data object is located in the PDO depends on the ENI file used. | ||
| - | These offsets must be read from the ENI file and configured in //" | ||
| - | |||
| - | All methods above the low level methods are optional. | ||
| - | They contain a certain degree of intelligence and simplify the interface to the user application. | ||
| - | |||
| - | ===== Blocking functions ===== | ||
| - | Methods in the interface must never be **blocking**. | ||
| - | |||
| - | Some advanced functions may take several cycles. | ||
| - | They are only completed when they return '' | ||
| - | These methods must be called again in each cycle until they return '' | ||
| - | |||
| - | ==== Advanced set functions ==== | ||
| - | All advanced set functions with a boolean return value have to be called multiple times until they return true. | ||
| - | This is because the drives may need to run through multiple state changes and may have to send different commands depending on the state of the drive. | ||
| - | Call this methodes every cycle of your control system until it returns true. | ||
| - | |||
| - | ==== Advanced get functions ==== | ||
| - | This methodes implement additional logic to interpret the data from the EC bus and return a sensible value. | ||
| - | |||
| - | === getPosition / getPositionAux === | ||
| - | The methodes //" | ||
| - | The difference is added to the stored position (int64_t). | ||
| - | This approach prevents an overflow of a 32 bit integer. | ||
| - | |||
| - | These methodes consider a fixed offset as well. | ||
| - | The offset may be set with the index pulse (see below). | ||
| - | |||
| - | === Gain scheduling functions === | ||
| - | This functions are implemented for backwards compatibility are probably not used. | ||
| - | |||
| - | |||
| - | ==== Basic funcitons ==== | ||
| - | These functions provide some basice conversions for ease of use. | ||
| - | |||
| - | |||
| - | |||
| - | |||
| - | ===== EtherCatInterfaceElmo_config.hpp ===== | ||
| - | This is configuration file has do be adapted depending on the EtherCAT network. | ||
| - | |||
| - | The most important part of this file is the offset definition of all PDO offset. | ||
| - | Before you start your application, | ||
| - | |||
| - | Be aware that EtherCATInterface assumes that all drives send the identical variables via PDO. | ||
| - | With the current implementation it is not possible to send different variables for different drives. | ||
| - | |||
| - | If a variable is not available, the offset is set to a negative number like ' | ||
| - | The methods which would use a unavailable variable will throw an error if called. | ||