Couplers and links seem to serve relatively similar purposes in PROFIBUS networks at first, but actually, they are very different. This article will tell you all you need to know about how they differ and when to use which one.

Couplers vs links

Couplers

First up, couplers! Actually, in the instrumentation world, couplers act more like counselors. They send physical bus characteristics between PROFIBUS DP and PROFIBUS PA networks, mostly in simple. Furthermore, they do so transparently, bringing the networks together and slipping them the room key rather than directing the action.

Couplers counseling PROFIBUS
PROFIBUS – Courtesy of PROFIBUS International

You can use couplers in explosive and non-explosive places, which we in the industry call ex and non-ex. Keep in mind, though, that in the ex, you can only have so many devices in each segment for safety reasons.

Links

Now let’s talk about links. They see a little more action than couplers because they can switch. This means that links act as slaves in PROFIBUS DP and masters in PROFIBUS PA. They also support larger networks than couplers. Each link has a physical address and allows up to five couplers to connect with them.

Other resources that might interest you

PROFIBUS DP/PA remote configuration
Can you bypass your PLC with remote access if you have a PROFIBUS network.

FOUNDATION Fieldbus architecture
What architecture can you build in an FF system?

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