Fieldbus cable interference


Thread Starter

Nathan Williams

I am working a project using Fieldbuss cable( 2 pair twisted shield size #18). These cables will be ran in a cable tray for instrumentation cables only ( 120 volts or less). My question is, If there are any cables that have a "Digital" signal on them, will it cause any interference to the Fieldbuss cable? Also, what if any, effect does "Digital" signal have on Fieldbuss cable? Any information that you could send me would be greatly appreciated.


Zan Von Flue

Actually Digital or 230 signals should not effect the fieldbus information because a fieldbus controller can, through parity and such, check if the information is correct or not. However, the signal itself can be effected. If the controller finds bad information it could 'ask' for the information again, or throw it away and wait for the next package of information, slowing the communication down!


Verhappen, Ian

Fieldbus is designed to operate on individually twisted pair shielded cables, including multiconductors so as long as you follow the same
'guidelines' as with traditional analogue cables you should not have any difficulty. Digital signals by their nature are more immune to EMI/RFI
interference and the Fieldbus specifications are VERY conservative.
Therefore if you adhere to the cabling rules in the fieldbus specifications you will not have any problems. IF you need a summary of these design rules, Adobe Acrobat documents with this information are available from and

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