CI854 - BAUDRATE
In General, AFIK,
If Profibus cable length is
100mt - 3 to 12 M baudrate is set
200mt- 1 to 1.5 M baudrate is set
400mt- 500K baudrate is set
1000mt-187.5K baudrate is set
1200mt-93.5K baudrate is set
My doubt is in between two CI840, if i use a media converter (like SITECH or Hirschmann) on what basis is the speed of CI854 determined?
To be Precise My Profibus cable length is 200mtrs approx. but in between two nodes there is 400mt Optical Cable. In that case how should i choose the baudrate. Any Calculations available?
Voted best answer
Those length restrictions apply to the copper part of the bus. For your application where the optical fibre is short, ignore it. Your copper cable length is 200m - so stick with the default 1.5M speed unless your devices require something else.
Max fibre length is around 15 km
Hello, As Rob said in the other reply, these cable length restrictions apply to copper cable. For optical cable the max limit is 15 KM. but you have to consider the additional impact on bus timing due to introduction of media converters. Read the Media converter's documentation, it will specify how much delay it will introduce, you have to set the timing parameters on profibus accordingly. Maybe only increase slot time a bit. (for 1.5Mbps, the minimum slot time recomended is 530tbit, where as the default value in CI854 is 300tbit)
If you keep the baudrate at 1.5 Mbps and use calculation method as "actual value based" this should work fine.
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