PROFIBUS Manual

Interrupting connectors

Interrupting connectors

Previous topic Next topic  

Interrupting connectors

Previous topic Next topic JavaScript is required for the print function Mail us feedback on this topic!  

Modern PROFIBUS connectors have one cable input marked "ingoing" and one cable output marked "outgoing". This differentiation is very important, because the plug will switch off the cable output if the termination resistor is switched on. Connectors like this are very useful for testing and commissioning a network. If such a connector in the middle of a segment has a termination switched on, the part of the segment connected to the output will be isolated while the remaining network will still be correctly terminated. For this reason, the first and last connectors must only use an "ingoing" cable input.

 

clip0084

 

Connectors often have a built-in switch that interrupts the bus if the bus termination is switched on.

clip0085

 

At the end and beginning of the bus, the cable must only be inserted at the input.

clip0086

 

In the middle of a bus segment, both  cables are connected. The cable input leads to the master.

 

If a connector does not have a breaker, it is not obvious when additional bus terminations are switched on. The signal will be damped by the additional bus termination and sporadic transmission faults may arise.

 

 

clip0107

 

When interrupting connectors are used, switching on an additional bus termination will inevitably lead to interruption of the bus and therefore to a static and easily identifiable error.

 

clip0108

D-type connector

Connector with bus termination switched on

Connector with bus termination switched on and breaker