Siemens SIMATIC S7-400 Reference Manual page 49

INTF, 5 VDC, 24 VDC LEDs
The following table shows the faults indicated by the INTF, 5 VDC, and 24 VDC LEDs and lists
how to remedy the faults. The status of the BAF, BATTF, BATT1F, and BATT2F LEDs is not
relevant here.
Table 3-7
INTF
LED
D
D
H
H
D
D
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
INTF, 5 VDC, 24 VDC LEDs
LED LED
DC5V DC24V
D D Standby switch in
Line voltage missing
Internal fault, power supply module
defective
Cutoff after overvoltage on 5 V or
non-permissible external supply
Power supply module operated in
wrong slot
Short-circuit or overload on 5 V
H D Overvoltage on 24 V
D* D Short-circuit or overload on 5 V and
24 V and overheating
H D If the standby switch is set to the
position, illegal external supply on
5 V
If the standby switch is set to the |
position, short-circuit or overload on
24 V.
B H Voltage restored after short-circuit or
overload on 5 V if faults occur in op‐
eration
Dynamic overload on 5 V
B B Voltage restored after short-circuit or
overload on 5 V and 24 V if faults oc‐
cur in operation
3.5 Fault/Error messages via LEDs
Cause of fault
position
Power supply modules
Remedy
Set standby switch to the | posi‐
tion
Check line voltage
Replace power supply module
Disconnect from mains and recon‐
nect after approximately 3 mi‐
nutes; if necessary, remove exter‐
nal supply
Install the power supply module in
the correct slot (slot 1)
Switch off the power supply mod‐
ule, remove the source of the
short-circuit; after approximately 3
seconds, the power supply mod‐
ule can be switched on with the
standby switch or via the power
system.*
Check if there is an external sup‐
ply; if not, replace power supply
module.
Check the load on the power sup‐
ply module. Remove module if
necessary. Wait 5 minutes before
switching the power supply mod‐
ule again.
Remove all modules; determine
which module is faulty.
Check the load on the power sup‐
ply module. Remove module if
necessary.
Press FMR button: Flashing
changes to steady light
Check load on the power supply
module. Possibly remove mod‐
ules.
Press FMR button: Flashing
changes to steady light
49