6 Buscoupler startup and troubleshooting

After configuration of the master connection and electrical installation of the fieldbus node/station, operation of the system can begin.

After power to the Buscoupler and I/O modules has been applied, the Buscoupler verifies all internal functions, components and the communication interface by an internal diagnostic routine. Then the function modules and the existing configuration is determined. At the same time a hidden file is stored. It consists of an input and an output area which is located on the fieldbus RAM of the log chip. During the power up phase the ‘I/O ERR’ LED flashes with an increased frequency. After a faultless power up the fieldbus coupler enters the state ‘fieldbus start’. The green LED ‘RUN’ indicates that the Bus is operating normally.

In case of a fault the red ‘I/O ERR’ LED will continue flashing.

By counting the number and frequency of flashes the fault can be easily identified quickly and accurately. A varying number of flashes and frequencies defines the fault. The table below describes the fault condition based on the counted number of ‘I/O ERR’ LED flashes.

Table 5: Diagnosis LEDs - on buscoupler

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After elimination of the fault, the buscoupler can only be set to the normal working condition by another POWER ON sequence.

The green I/O LED flashes when accessing the I/O modules internal data channels. After being switched on, the buscoupler queries the configuration of the bus modules but does not carry out a data exchange with the I/O modules. This means that the red I/O LED will extinguish after a faultless startup. The green I/O LED will indicate when data is being exchanged by the Interbus network.

Status and error diagnostics:

The fieldbus LEDs show the state of the bus system. The functions of Interbus S are shown by the LEDs „READY“, „BA“, „RC“ and „RD“.

Table 7: Diagnostic LEDs - fieldbus

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