106 • PROFINET IO 750-340Error ResponseWAGO-I/O-SYSTEM 750PROFINET IO3.1.10 Error Response3.1.10.1 Fieldbus FailureA fieldbus failure is indicated if the I/O controller switches off or if theEthernet cable is interrupted. An error in the I/O controller can also lead to afieldbus failureThe red BF LED lights up.When the fieldbus fails, the coupler can release the configurable substitutevalues of the I/O modules. A substitute value can be determined for eachchannel when configuring the outputs.Substitute valuestrategyValue (bit orientated)Digital Output ModulesValue (byte orientated)Analog Output ModulesMinimum value 0 0 or. 4 mA, -10 or. 0 VMaximum value 1 20 mA, 10 VSubstitute value 0 or 1 0/4 ... 20 mA, -10/0 ... +10 VStop internal bus Response determined by the I/O moduleThe values are entered into the output process image by the coupler. With I/Omodules that have a byte orientated data width (e.g. pulse width module), thesubstitute value is determined using the value range.As soon as the fieldbus is reactivated, the process data is transmitted again andthe outputs of the node are set accordingly.3.1.10.2 Internal Bus FailureAn internal bus failure occurs, for example, if an I/O module is removed. Ifthis error occurs during operation, the output modules react like during aninternal bus stop. The input process image is set according to the configurationstrategy.The "I/O" LED flashes red. The buscoupler (I/O device) generates a detaileddiagnostic message.When the I/O module fault is repaired, the buscoupler restarts according to theconfigured restart behavior. The process data is transmitted again and theoutputs of the node are set accordingly.
