Siemens SIMATIC S7-1500 CPU 1511-1 PN

RUN/STOP LED ERROR LED MAINT LED Meaning
Startup (CPU booting)
Test of LEDs during startup, inserting a module.
LED flashes
yellow/green
LED flashes red LED flashes yellow
LED flashing test
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
ports.
Table 5-2Meaning of the LEDs
LINK TX/RX LED Meaning
LED off
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.
LED flashes green
The "LED flashing test" is being performed.
LED lit green
There is an Ethernet connection between the PROFINET interface of your PROFINET device and
a communication partner.
LED flashes yellow/green
Data is currently being received from or sent to a communications partner on Ethernet via the
PROFINET interface of the PROFINET device.
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.
Meaning of the STOP ACTIVE LED
The following table shows the meaning of the STOP ACTIVE LED of the CPU.
Table 5-3Meaning of the LEDs
STOP ACTIVE LED Meaning
LED lit yellow
The CPU is switched to "STOP" mode using the STOP button.
• As long as the STOP ACTIVE LED is lit up, switching the CPU to RUN mode is only possible
using the RUN button.
• The CPU can then no longer be set to RUN mode via the display operation or via online func
tions. The state of the buttons is retained at power-off. If the CPU does not start up automat
ically after a power-on, you have to keep the STOP button pressed during start-up until the
STOP ACTIVE LED is activated.
• If an automatic start-up is to be reliably prevented after a power-up, the STOP button has to
be kept pressed during the start-up of the CPU until the STOP ACTIVE LED is activated.
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CPU 1511-1 PN (6ES7511-1AL03-0AB0)
Equipment Manual, 11/2022, A5E40869673-AC
Interrupts, error messages, diagnostics and system alarms
5.1 Status and error display of the CPU