Using 2 cables on a Profibus connector

[udit_91]

Hi,

I was noticing that Profibus connectors have 2 ports on them that can house 2 separate cables. Can I use 2 cables with Profibus signals coming on them on the same connector and have signals coming in from both cables to the one connector?

 

[Ken Moore]

Profibus can only have one "Master" on a network.

 

[AlfredoQuintero]

PROFIBUS is a bus. The reason you see two ports is because unless the node is the last node of the segment, the PROFBUS connector is designed to make it easy to assemble a "daisy-chain". The three lines of the PROFIBUS connector are connected or shorted inside the connector.

Here you will find some free of charge literature that I hope will be useful
PROFIBUS Installation Guidelines
PROFIBUS Interconnection Technology

 

[CM3]

So profibus is like a chain; each connector creates a node (or an access point) on the chain. The first connector should be at the master (usually a PLC) and needs termination (to tell the chain it is an end). From the first connector, the cable is run to the second connector (in and out) then to the third connector (in and out) and so on until you reach the last device where the cable will run in, and then the termination resistor is turned on. If you are using field devices (not cabinet devices) it is common to run in one connector and out the other - but for cabinet devices that use the 9 pin connector, it is common that the cable can run in/out on one connector (as it uses multiple pins instead of just two).

 

[Ken Moore]

Also, the last powered node, needs to have the termination resistor. This often causes issues in Motor Control Centers (MCC), where one or more "buckets" gets powered down and the others are still active. I always use Siemens end of line powered terminations when using profibus in a MCC, but I'm sure there are other vendors.