Siemens SIMATIC ET 200SP Manual page 65

"AS-i OK" LED
Table 8- 3 Meaning of the AS-i OK LED
AS-i OK Meaning
An error has occurred (see AS-i FAULT LED) or the AS-i master is offline. This means:
No I/O data exchange is taking place, e.g., during power-up.
OFF
The AS-i bus is fault-free. I/O data exchange takes place.
Green ON
"AS-i FAULT" LED
Table 8- 4 Meaning of the AS-i FAULT LED
AS-i FAULT Meaning
No AS-i cable faults have occurred.
The AS-i master is in "Offline" mode.
Red OFF
The AS-i bus has failed, e.g. the supply voltage for AS-Interface is too low, ground fault.
Red ON
A fault has occurred, e.g. a duplicate address or parameterization error has been detected.
Red "flashes"
AS-Interface master CM AS-i Master ST (3RK7137-6SA00-0BC1)
Manual, 07/2017, A5E02655262020A/RS-AD/004
Alarms, faults and system events
8.3 LED statuses
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