EtherCAT Application Workflow

Developing IgH Applications

6.1 Development Workflow

An IgH application is generally initialized in the following order:

1. Obtain the master with ecrt_request_master().
2. Create a process data domain with ecrt_master_create_domain().
3. Configure slaves by alias, position, Vendor ID, and Product Code with ecrt_master_slave_config().
4. Configure Sync Managers and PDOs with ecrt_slave_config_pdos().
5. Register the PDO entries accessed by the application with ecrt_domain_reg_pdo_entry_list().
6. Configure DC, SDOs, watchdogs, and slave-specific parameters as needed.
7. Activate the master with ecrt_master_activate().
8. Obtain the process data memory with ecrt_domain_data().
9. Enter the fixed-period real-time loop.
10. Before exiting, stop outputs, release the master, and restore a safe state.

Request master → Create domain → Configure slaves and PDOs → Activate master
                                                   │
                                                   ▼
Receive → Process domain → Read inputs → Write outputs → Queue → Send
   ▲                                                               │
   └──────────────────── Fixed-period loop ─────────────────────────┘

6.2 Generating a PDO Configuration Reference

Connect and power on the slaves, then run:

ethercat slaves
ethercat pdos -p 0
ethercat cstruct -p 0

Use the cstruct output as a starting point for the application configuration. Remove unnecessary entries or adjust the PDO mapping according to the slave manual. Confirm the Vendor ID and Product Code with:

ethercat slaves -v
ethercat xml -p 0

Do not match slaves only by device name. The application should validate the Vendor ID and Product Code and, when necessary, the Revision Number.