Siemens SIMATIC S7-1500 Manual page 24

Diagnostics
7.1 Status and error displays
LED displays RUN/ERROR/MAINT
Table 7- 1 Meaning of the LEDs RUN / ERROR / MAINT
LEDs
RUN ERROR MAINT
Off Off
Flashes Off
On Off
On Flashes
Flashes Flashes Flashes
PWR LED display
Table 7- 2 Meaning of the PWR LED display
LED PWR
Off
On
22
Meaning
No or too little supply voltage via backplane
bus.
Off
The technology module starts and waits
until the valid parameter assignment is set.
Off
Parameter assignment of the technology
module is valid.
Off
Module error, e.g. no supply voltage
Off
Firmware update running.
Communication between AI-capable proces-
sor and backplane bus is faulty.
Hardware or firmware defective.
Meaning
External supply voltage too low or missing.
External supply voltage available.
Remedy
• Switch on the CPU or IM and/or the
system power supply modules.
• Check that the U connectors are insert-
ed.
• Check whether too many modules are
inserted.
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Check the supply voltage.
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• Switch the supply voltage off and on
again.
• Switch off the supply voltage, download
files for the application and neural net-
work, switch on supply voltage again.
Replace the technology module.
Remedy
Check the external supply voltage.
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Technology Module TM NPU
Equipment Manual, 09/2020, A5E46384784-AA