Siemens SIMATIC S7-1500 Manual page 35

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 the
CPU 1518‑4 PN/DP ports.
Table 5-2 Meaning of the LEDs
LED flashes green
NOTE
"LED" instruction
You can read the status (e.g. "On" or "Off") of LEDs of a CPU or a module using the "LED"
instruction. Note, however, that it is not possible to read the LED status of the LINK RX/TX
LEDs on all S7-1500 CPUs.
You can find additional information on the "LED" instruction in the STEP 7 online help.
CPU 1518-4 PN/DP (6ES7518-4AP00-0AB0)
Equipment Manual, 11/2022, A5E32334527-AE
ERROR LED
LED flashes red
LINK TX/RX LED
There is no Ethernet connection between the PROFINET interface of the
LED off
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
LED lit green
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.
LED flashes yel­
low/green
Interrupts, error messages, diagnostics and system alarms
MAINT LED
Startup (CPU booting)
LED flashes yellow
Test of LEDs during startup, inserting a module.
LED flashing test
5.1 Status and error display of the CPU
Meaning
Meaning
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