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| Nächste Überarbeitung | Vorhergehende ÜberarbeitungLetzte ÜberarbeitungBeide Seiten der Revision | ||
| embedded_systems:ethercatinterface:ethercatinterfaceelmo [2019-05-21 08:40] – angelegt mgehrig2 | embedded_systems:ethercatinterface:ethercatinterfaceelmo [2019-05-21 09:25] – mgehrig2 | ||
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| - | ====== EtherCATInterfaceElmo ====== | + | ====== 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. | ||