Siemens SIMATIC S7-1500 Equipment Manual page 22

Meaning of the LED displays
The following table explains the meaning of the status and error displays.
RUN and ERROR LED
Table 5- 1 RUN and ERROR status and error displays
LED
RUN ERROR
Off Off
Off
Flashes
On Off
Flashes Flashes
CHx LED
Table 5- 2 CHx status display
LED CHx
Off
On
Digital output module DQ 16x230VAC/1A ST Triac (6ES7522-5FH00-0AB0)
Equipment Manual, 12/2021, A5E34934069-AC
Meaning
Voltage missing or too low at backplane bus
The module starts and flashes until the valid
parameter assignment is set.
Module parameters assigned
Hardware defective
Meaning
0 = Status of the output signal
1 = Status of the output signal
5.1 Status and error displays
Solution
• Switch on the CPU and/or the system power
supply modules.
• Verify that the U connectors are inserted.
• Check whether too many modules are in-
serted.
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Replace the module.
Solution
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Diagnostic alarms
21