EtherCAT interface
54
AMS 338
i
Leuze electronic
Notice!
For the AMS 338
i
as standalone device or as the last participant in a linear topology, termi-
nation on the BUS OUT socket is not mandatory!
9.6
Starting the AMS 338
i
on the EtherCAT
INIT
The AMS 338
i
initializes itself. No direct communication between the master and AMS 338
i
is possible. The EtherCAT master will transit the AMS 338
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: AMS 338
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 AMS 338
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 measurement system into the save-operational
state. The master produces output data, but input data are not considered. This means the
AMS 338
i
does not return output data (=PLC input data) in SAFEOP. The AMS does not
process input process data (=PLC output data). Mailbox communication via CoE services
is possible.
OPERATIONAL
The "start output update" command puts the measurement system into OPERATIONAL
state. In this state, the AMS 338
i
supplies valid input data and the master valid output data.
After the AMS 338
i
has detected the data received via the process data service, the state
transition is confirmed by the AMS 338
i
. If the activation of the output data was not possible,
the measurement system remains in the SAFE OPERATIONAL state and outputs an error
message.
