BECKHOFF ET1200 - Manual (Page 12)

Overview
III-2 Slave Controller – ET1200 Hardware Description
1.1 Frame processing order
The ET1200 supports two ports (logical ports 0 and 1) or three ports (logical ports 0, 1, and 3). The
frame processing order of the ET1200 depends on the number of ports (logical port numbers are
used):
Table 2: Frame Processing Order
Number of Ports Frame processing order
2 0 →EtherCAT Processing Unit→1 / 1→0
3 0 →EtherCAT Processing Unit→3 / 3→1 / 1→0
Figure 2 shows the frame processing in general:
1
Port 1
A
u
to
-
F
o
rw
a
rd
e
r
1
Port 3
Auto-
Forwarder
Port 0
A
u
to
-
F
o
rw
a
rd
e
r
L
o
o
p
b
a
c
k
f
u
n
c
ti
o
n
EtherCAT
Processing Unit
Loopback function
L
o
o
p
b
a
c
k
f
u
n
c
ti
o
n
ET1200
p
o rt
1
c
lo
s e d
p
o rt
1
o
p
e n
port 3 open
port 3 closed
p
o rt
0
o
p
e n
o r
a ll
p o
rt s
c lo
s e
d
p
o rt
0
c
lo
s e d
Figure 2: Frame Processing