PROFIBUS Manual
All devices are connected in a bus structure (line). In one segment up to 32 stations (masters, slaves or repeaters) can be switched together. Rules regarding stub lines must be respected.
Each PROFIBUS segment must be terminated at the beginning and end and in no case include and bus termination between these ends. Some PROFIBUS devices have integral bus terminations that can be switched on and off. In such cases it is important for these bus terminations to be switched off. A common error is to have the bus termination in the connector and in the device switched on at the same time! This duplicate termination leads to a termination fault and hence to reflections.
In any one segment, it is important that terminations should be switched on and off in the right connectors. For this reason, the rules and a few examples are explained in detail here:
1.Optimum position of the masters and of bus terminations
2.Connection of more than 32 stations on one bus
3.Transmitting over a longer distance
5.Electrical isolation of individual segments on the bus
Additional possibilities result from the use of FOC converters.
