Siemens SIMATIC S7 System Manual page 634

107BOnline and diagnostic tools
14.1 Status LEDs
Description
Defective hardware
LED test or defective CPU firmware
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.
Status LEDs on an SM
In addition, each digital SM provides a DIAG LED that indicates the status of the module:
● Green indicates that the module is operational
● Red indicates that the module is defective or non-operational
Each analog SM provides an I/O Channel LED for each of the analog inputs and outputs.
● Green indicates that the channel has been configured and is active
● Red indicates an error condition of the individual analog input or output
In addition, each analog SM provides a DIAG LED that indicates the status of the module:
● Green indicates that the module is operational
● Red indicates that the module is defective or non-operational
The SM detects the presence or absence of power to the module (field-side power, if
required).
Table 14- 2 Status LEDs for a signal module (SM)
Description
Field-side power is off
Not configured or update in progress
Module configured with no errors
Error condition
I/O error (with diagnostics enabled)
I/O error (with diagnostics disabled)
634
STOP/RUN
Yellow / Green
On (yellow)
Flashing
(alternating yellow and green)
ERROR
Red
On
Flashing
DIAG
(Red / Green)
Flashing red
Flashing green
On (green)
Flashing red
-
-
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
MAINT
Yellow
Off
Flashing
I/O Channel
(Red / Green)
Flashing red
Off
On (green)
-
Flashing red
On (green)