Fault tracing 327Embedded fieldbus faultsEmbedded fieldbus faults can be traced by monitoring group 53 EFB PROTOCOLparameters. See also fault/alarm SERIAL 1 ERR. No master deviceIf there is no master device on line, parameter 5306 EFB OK MESSAGES and 5307EFB CRC ERRORS values remain unchanged.What to do:• Check that the network master is connected and properly configured.• Check the cable connection. Same device addressIf two or more devices have the same address, parameter 5307 EFB CRC ERRORSvalue increases with every read/write command.What to do:• Check the device addresses. No two devices on line may have the same address. Incorrect wiringIf the communication wires are swapped (terminal A on one device is connected toterminal B on another device), parameter 5306 EFB OK MESSAGESS value remainsunchanged and parameter 5307 EFB CRC ERRORS increases.What to do:• Check the EIA-485/RS-232 interface connection.
