Hi all,

Please, I'm getting confused with the limitation of ONE control loop for segment.

What does it mean?

The limitation is for the scan time or the power supply?

Could you give me some example?

 

This is NOT a constraint from the Fieldbus protocol. It is a practical constraint to make sure that traffic on the segment does not interfere with control loop timing. If you know that the control loop(s) are slow, then you can
have more loops per segment. It's just a matter of data throughput on the 31.25 kbps H1 link.

Dick Caro
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It is not limited to one loop per bus. You can have many loops per bus, even for fast loops.

UOP require 250/300 ms for many loops and we have met this requirement even with two loops per bus plus monitoring points.

A key to putting more loops per bus is using devices that execute blocks fast. Check on block execution time before purchasing devices.

Cheers,
Jonas