Programming manual SCU-series
HB-37500-820-10-12F-EN SCU Programming manual
Page 20 of 252
Status: 19.03.2021
3.2.3. FSoE and EtherCAT
The Ethernet frame of the EtherCAT network can contain non-safe as well as safe data. The safe
data are called FSoE data, and are assigned to the FSoE Master-and-Slave protocol stack. These
data are transferred cyclically, and are thus included in the PDO of the respective participant.
The SCU is designed as FSoE Master, and it starts the safe data transfer via FSoE. Furthermore,
as EtherCAT Slave, the SCU participates in the non-safe EtherCAT network.
A separate EtherCAT Master starts the non-safe data transfer via EtherCAT.
The PDOs with the included FSoE files are transmitted cyclically. The cycle time of the transfer is
fixed in the configuration of the EtherCAT -Masters. As a rule, it should be adjusted many times
shorter than the cycle time of the FSoE master to grant the update of the data within the Watchdog
control time of the FSoE Master.
The
SCU
(FSoE Master) starts the safe data transfer via FSoE, receives from the Slave groups (e.
g. SIO, SDU, SSB) the data from inputs and evaluates these data. Afterwards, the SCU can
implement safety functions, and can switch outputs accordingly
–
this can be done either by the
proper outputs of the units, or by the outputs of the Slave units.
Furthermore, as EtherCAT Slave, the SCU is participant in the non-safe EtherCAT network.
A separate EtherCAT Master starts the non-safe transfer via EtherCAT.
S
=
Safe
(Data Transfer) =
FSoE
N
=
Non-safe
(Data Transfer) =
EtherCAT
S
+
N
N
SCU
EtherCAT-Master
In Out
In Out
Slave
In Out
Slave
In Out
Slave
In Out
Slave
FSoE-Master
In Out
S
+
N
S
+
N
S
+
N
N
Figure 2: FSoE network