Interrupts, error messages and diagnostics and
system alarms
The status and error displays of the CPU 1518T‑4 PN/DP are described below.
You will find additional information on "Interrupts" in the STEP 7 online help.
You can find additional information on the topics of "Diagnostics" and "System alarms" in the
Diagnostics (https://support.automation.siemens.com/WW/view/en/59192926) function
manual.
5.1
Status and error display of the CPU
LED display
The figure below shows the LED displays of the CPU 1518T‑4 PN/DP.
①
②
③
④
⑤
⑥
⑦
⑧
Figure 5-1 LED displays of the CPU 1518T‑4 PN/DP (without front panel and display)
CPU 1518T-4 PN/DP (6ES7518-4TP00-0AB0)
Equipment Manual, 11/2022, A5E50479758-AB
RUN/STOP LED (yellow/green LED)
ERROR LED (red LED)
MAINT LED (yellow LED)
No function
LINK RX/TX LED for port X1 P1 (yellow/green LED)
LINK RX/TX LED for port X1 P2 (yellow/green LED)
LINK RX/TX LED for port X3 P1 (yellow/green LED)
LINK RX/TX LED for port X2 P1 (yellow/green LED)
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