Siemens SIMATIC S7-1500 Manual page 18

Meaning of the LED displays
The following table explains the meaning of the status and error displays.
RUN and ERROR LED
Table 5- 1 Status and error displays RUN and ERROR
LED
RUN ERROR
Off Off
Flashes Off
On Off
Flashes Flashes
CHx LED
Table 5- 2 CHx status display
LED CHx
Off
On
DI 16x230VAC BA Digital Input Module (6ES7521-1FH00-0AA0)
Manual, 07/2014, A5E03485975-AC
Meaning
Voltage missing or too low at backplane bus
Module starts up
Module is ready
Hardware defective
Meaning
0 = Status of the input signal
1 = Status of the input signal
5.1 Status and error displays
Remedy
Switch on the CPU and/or the system pow-
•
er supply modules.
Verify that the U connectors are inserted.
•
Check to see if too many modules are in-
•
serted.
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Replace the module.
Remedy
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Diagnostic alarms
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