CPUs for M7-400
11-7
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Meaning of the Status and Fault LEDs
The status and fault LEDs are explained in Table 11-4 in the order in which they are
arranged on the CPU 486-3 and CPU 488-3 modules. The following status and
fault LEDs are available:
Table 11-4 Meaning of the Status and Fault LEDs on the CPU 486-3 and CPU 488-3
LED Meaning Explanations
INTF (red)
EXTF (red) Internal or external
fault indicator Lights up in the event of:
•Hardware faults
•Firmware faults
•Programming faults
•Parameter assignment faults
•Computational faults
•Timer faults
•Memory card faults
•I/O faults
Use the programming device for precise fault-finding
(read out diagnostic buffer).
SD (green) Access to memory
card Lights up if read or write access to the memory card is
taking place.
HD (green) Hard disk access Lights up if read or write access to the hard disk of the
mass storage module is taking place
USR1
(yellow) Special LED for
the user program
(User)
Can be assigned by the user (see Programming
Manual)
USR2
(yellow) Special LED for
the user program
(User)
RUN
(green) “RUN” state LED Lights up if the system software is loaded and user
programs are running
(I/O access enabled).
STOP
(yellow) “STOP” state LED •Lights up when the user program of the
programmable module is not controlling the
process (I/O access disabled)
•Flashes when a memory reset is requested or is
being performed