Siemens simatic s7-400 FM 450-1, User Manual, Page: 108 / 130

Errors and diagnostics
11.5 Operator error
Counter module FM 450-1
108
Manual, 02/2014, A5E03648739-02
11.2 Faults indicated via the diagnostics LEDs
Where are the faults displayed?
Faults are indicated by the two red diagnostics LEDs:
● The INTF diagnostics LED displays internal faults of the module.
● The EXTF diagnostics LEDdisplays external faults to the cable connections.
Which fauts are displayed?
The following faults are indicated by the two red diagnostics LEDs lighting up:
Fault type/LED Cause of fault Correction
Internal fault
INTF diagnostics LED Fault in EPROM TEST Module replacement
Fault in RAM TEST Module replacement
Watchdog has responded Module replacement
Process interrupt lost Is acknowledged by processing the process
interrupt.
External fault
EXTF Diagnostics LED Auxilliary voltage 1L+/1M is not connected or
24 VDC encoder supply is short circuited
Correct connection
5.2 VDC encoder supply short circuited or
overloaded
Correct connection
5 V encoder signals faulty (wire breakage,
short circuit, cable missing)
Correct connection
Initiation of a diagnostics interrupt
All faults, except for the fault in the EPROM test can initiate a diagnostics interrupt if you
have enabled the diagnostics interrupt in the relevant parameter assignment screen form.
You will find out which fault has caused the LED to light up from the diagnostic data records
DS0 and DS1. The assignment of the diagnostics data records DS0 and DS1 is described in
the next section.