Siemens Simantic S7-1500 Manual page 36

Interrupts, error messages, diagnostics and system alarms
4.1 Status and error displays of the CPU
RUN/STOP LED
LED flashes
yellow/green
Meaning of LINK RX/TX LED
Each port has a LINK RX/TX LED. The table below shows the various "LED scenarios" of
ports for the CPU 1517T-3 PN/DP.
Table 4- 2 Meaning of the LEDs
LINK TX/RX LED
LED off
LED flashes green
LED lit green
LED flickers yellow
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ERROR LED
LED flashes red LED flashes yellow
There is no Ethernet connection between the PROFINET interface of the PROFINET device
and the communication partner.
No data is currently being sent/received via the PROFINET interface.
There is no LINK connection.
The "LED flashing test" is being performed.
There is an Ethernet connection between the PROFINET interface of your PROFINET
device and a communication partner.
Data is currently being received from or sent to a communications partner on Ethernet via
the PROFINET interface of the PROFINET device.
MAINT LED
Startup (CPU booting)
Test of LEDs during startup, inserting a module.
LED flashing test
Meaning
Meaning
CPU 1517T-3 PN/DP (6ES7517-3TP00-0AB0)
Manual, 12/2017, A5E36285525-AB