Leuze electronic GmbH + Co. KG
MA 238
i
48
INIT
The MA 238
i
initializes itself. No direct communication between the master and MA 238
i
is possible. The
EtherCAT master will transit the MA 238
i
step by step into the "operational" state.
In the status change from "INIT" to "PREOP", the TwinCAT or master writes the so-called EtherCAT
address (=station address) to the respective register of the EtherCAT slave controller (here: MA 238
i
). This
EtherCAT address is typically specified in relation to the position, i.e., the master's address is 1000, the
first slave's address is 1001, etc. This is also called the auto-increment method.
PRE-OPERATIONAL
The master and the MA 238
i
exchange application-specific initializations and device-specific parameters.
In the PRE-OPERATIONAL state, configuration is initially possible via SDOs only.
SAFE-OPERATIONAL
The "Start Input Update" command puts the gateway into the "Safe-Operational" state. The master
produces output data, but input data is not considered. This means the MA 238
i
does not return output
data (= PLC input data) in SAFEOP. The gateway does not process input process data (=PLC output
data). Mailbox communication via CoE services is possible.
OPERATIONAL
The "Start Output Update" command puts the gateway into the OPERATIONAL state. In this state, the
MA 238
i
supplies valid input data and the master valid output data. After the MA 238
i
has detected the
data received via the process data service, the state transition is confirmed by the MA 238
i
. If the activation
of the output data was not possible, the gateway remains in the SAFE OPERATIONAL state and outputs
an error message.
12.5 CANopen over EtherCAT
EtherCAT provides the communication mechanisms described below. In this context, the SDO accesses
to the online dictionary via CoE (CANopen over EtherCAT) are carried out via mailbox services. PDO
services via CoE mailboxes are not supported.
• Object index
• PDO, process data object
• SDO, service data object
• NMT, network management
Master and slave must be located in the same EtherCAT network.
12.5.1 Device profile
The device profile describes the application parameters and the functional behavior of the MA 238
i
. For
EtherCAT, one does not specify individual device profiles for device classes. Instead, simple interfaces for
existing device profiles are provided.
12.5.2 Device description file
For EtherCAT, all process data and parameters are described in objects. The compilation of all process
data and parameters of the gateway - the object directory - is stored in a so-called ESI file (EtherCAT Slave
Information).
The ESI file contains all objects with index, sub-index, name, data type, default value, minimum and
maximum, and access possibilities. That means the ESI file describes the entire functionality of the
MA 238
i
, and it is possible to adjust both the communication of the gateway with the control and the
RS 232 interface.
