1, sensor signal is given: the field wiring is not standardized, and the control line, signal line and high voltage are mixed together, which will cause signal interference when high-power equipment is started, and this situation will also occur. I suggest you check the direction of the Frophibus line. B indicates that there is something wrong with the module, or the connecting wire is white, and the module is powered on and grounded.
2. The signal of the sensor is not extinguished. Check the wiring, power supply and necessary grounding of the sensor. SF light indicates system failure, including many types. The specific fault types can be viewed online through CPU.