Table 5- 3 Possible States Of The Link And Rx/Tx Leds - Siemens SIMATIC S7-400H System Manual

Assembly of a CPU 41x–H
5.3 Status and error displays
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
Lit Irrelevant
Irrelevant Flashes
6 Hz
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
Flashes Link-up
0.5 Hz
Flashes Update
2 Hz
Dark Redundant (CPUs are redundant)
Lit Redundant (CPUs are redundant)
58
Meaning
Connection at the PROFINET interface is active
Receiving or sending data at the PROFINET interface.
Basic requirements
-
-
No redundancy error
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

System Manual, 03/2012, A5E00267695-11
S7-400H