State machine

Configuration of the EL6731-0010 with StartUp SDOs:

The following flow chart shows the sequence of the configuration of the EL6731-0010 with StartUp SDOs:

Following a power-on, the EL6731-0010 is in the INIT state and has no DP configuration. The EL6731-0010 is not active on the PROFIBUS.

DP slave configuration

The DP configuration is carried out via SDO download in the PREOP state. The objects to be loaded must be transmitted either with Complete Access or with consistency nesting (first set SubIndex 0 to 0, then write SubIndex 1-n, then set SubIndex 0 to n). Care should thereby be taken to always start with object 0xF800. The DP CfgData are to be transferred with object 0x8002. After the receipt of object 0x8000, the EL6731-0010 is active on the PROFIBUS (FDL only, no DP). The EL6731-0010 supports automatic baud rate search, therefore no baud rate need be configured.

PDO Mapping

There is an EtherCAT RxPDO (if the DP slave has DP inputs (is sent to the DP master)) and an EtherCAT TxPDO (if the DP slave has DP outputs (is received from the DP master)). The PDO mapping of the EtherCAT PDOs is automatically calculated by the EL6731-0010 after the download of the respective 0x8yyz objects and can be read. The PDO mapping objects can only be written with the values that the EL6731-0010 has calculated itself. The writing of the PDO mapping thus serves only to check the PDO mapping calculated by the EtherCAT configurator and can therefore be omitted.

PDO Assign

Additionally there is an EtherCAT PDO that contains status information. This PDO is selected via the PDO Assign. With regard to the order of the PDOs in the PDO Assign, it is important to ensure that the index of the assigned EtherCAT PDO increases with each entry in the corresponding PDO Assign object. If the EtherCAT master does not transfer a PDO Assign to the StartUp SDOs, then the PDO 0x1A7F is assigned for the status.

Cyclic DP communication

During the transition to SAFEOP, the EL6731 checks the length configured in the Sync Manager channels 2 and 3 against the length calculated from PDO Mapping and PDO Assign. The SAFEOP state is only adopted if these lengths match. The DP function of the EL6731-0010 is active in the SAFEOP state. As long as the EL6731-0010 is in SAFEOP, the DP input data that are sent to the DP-master are set to 0. As soon as the EL6731-0010 has been switched to OP, the data from the EtherCAT outputs are transmitted to the DP master.

The EL6731-0010 runs independently of the EtherCAT cycle.

Configuration of the EL6731-0010 with Backup Parameter Storage

The following flow chart shows the sequence of the configuration of the EL6731-0010 with Backup Parameter Storage:

Following a power-on, the EL6731-0010 is in the INIT state and has no DP configuration. The EL6731-0010 is not active on the PROFIBUS.

DP bus parameters / DP slave configuration

The configuration stored in the Backup Parameter Storage object 0x10F2 is loaded during the transition from INIT to PREOP. Since the StartUp SDOs from the Configuration of the EL6731-0010 with StartUp SDOs are stored in the Backup Parameter Storage object, the sequence is the same as the one described there. Hence, the stored data is initially written to object 0x8000 and the EL6731-0010 is active on the PROFIBUS with automatic baud rate search. Subsequently, DP slave configuration is generated in object 0x8002. If the PREOP state is quit, the current DP configuration can be read from objects 0x8000 and 0x8002.

PDO Mapping / PDO Assign

In addition, the EtherCAT master can also read the PDO Mapping and PDO Assign in the PREOP state in order to determine the lengths of the EtherCAT process data.

Creating the Backup Parameter Storage

The Backup Parameter Storage can be created as follows:

1. Download object 0x10F2 (in PREOP without having sent StartUp SDOs beforehand): in this case the data received will be saved as Backup Parameter Storage in the flash memory

Deleting the Backup Parameter Storage

In order to load a new Backup Parameter Storage or to simply delete the existing one, the value 0x64616F6C has to be written to entry 0x1011:01.