Online and diagnostic tools
14.1 Status LEDs
S7-1200 Programmable controller
784 System Manual, 03/2014, A5E02486680-AG
Maintenance requested
• Forced I/O
• Battery replacement
required (if battery board
installed)
On (either yellow or green) - On
LED test or defective CPU
Flashing
(alternating yellow and green)
Flashing Flashing
Unknown or incompatible
version of CPU configuration
On (yellow) Flashing Flashing
Note
"Unknown or incompatible version of CPU configuration" error
Attempting to download an S7
-1200 V3.0 program to an S7-1200 V4.0 CPU causes a CPU
error, and the CPU displays a corresponding error message in the diagnostic buffer. If you
reached this state by using an invalid version
program transfer card (Page 127), then
remove the card, perform a STOP to RUN transition, a memory reset (MRES) or cycle
power. If you reach this state by an invalid program download,
reset the CPU to factory
(Page 789). After you recover the CPU from the error condition, you can download a
The CPU also provides two LEDs that indicate the status of the PROFINET communications.
Open the bottom terminal block cover to view the PROFINET LEDs.
● Link (green) turns on to indicate a successful connection
● Rx/Tx (yellow) turns on to indicate transmission activity
The CPU and each digital signal module (SM) provide an I/O Channel LED for each of the
digital inputs and outputs. The I/O Channel (green) turns on or off to indicate the state of the
individual input or output.
S7-1200 behavior following a fatal error
If the CPU firmware detects a fatal error it attempts a defect-mode restart, and if successful,
signals the defective mode by continually flashing the STOP/RUN, ERROR and MAINT
LEDs. The user program and hardware configuration are not loaded following the defect-
mode restart.
If the CPU successfully completes the defect-mode restart, the CPU and signal board
outputs are set to 0, and the outputs of central rack signal modules and distributed I/O are
set to the configured "Reaction to CPU STOP".
To Next Page
Loading...
