Assembly of a CPU 41x–H
5.3 Status and error displays
S7-400H
58
System Manual, 03/2012, A5E00267695-11
LINK and RX/TX LEDs
The LINK and RX/TX LEDs indicate the current state of the PROFINET interface.
Table 5- 3
Possible states of the LINK and RX/TX LEDs
LED
LINK
RX/TX
Meaning
Lit
Irrelevant
Connection at the PROFINET interface is active
Irrelevant
Flashes
6 Hz
Receiving or sending data at the PROFINET interface.
Note
The LINK and RX/TX LEDs are located directly next to the PROFINET interface sockets.
They are not labeled.
REDF LED
The REDF LED indicates specific system states and redundancy errors.
REDF LED
System state
Basic requirements
Flashes
0.5 Hz
Link-up
-
Flashes
2 Hz
Update
-
Dark
Redundant (CPUs are redundant)
No redundancy error
Lit
Redundant (CPUs are redundant)
There is an I/O redundancy error:
Failure of a DP master, or partial or total failure of a
DP master system
Loss of redundancy on the DP slave
Loss of redundancy at the PN IO device