Siemens SIMATIC ET 200SP Manual page 29

Meaning of the LEDs of the interfaces: X1 P1 R, X1 P2 R and X1 P3
Each port has a LINK LED (LK1, LK2, LK3). The table below shows the various "LED
scenarios" of the ports of the CPU 1510SP-1 PN.
Table 4- 2
LED flashes green
CPU 1510SP F-1 PN (6ES7510-1SJ00-0AB0)
Manual, 12/2014, A5E35264953-AA
Meaning of the LED
LINK LED
There is no Ethernet connection between the PROFINET interface of the
PROFINET device and the communication partner.
LED off
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.
LED lit green
Interrupts, error messages, diagnostics and system alarms
4.1 Status and error display of the CPU
Meaning
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