Class I Div I Intrinsically Safe Using RS-485 Daisy-Chain Protocol

[mkmorris]

I was wondering if I daisy chained two (2) transmitters via RS-485 on the hazardous side, to feed back to a barrier (isolator) on the safe side which will then feed back to a computer, and I still within bounds of intrinsic protection? Typical RS-485 driving voltage is around +12V if I remember correctly, but my concern was more with 2 processes coming into one line and being able to alter the signal on the cable depending on the process monitored. The voltage is still fairly low that I think I would still be within bounds. Capacitance of the cable is also extremely low.

This is all to receive a signal from the Magnetrol Contour transmitter to be used for Acoustic Volume Mapping of the inside of a bin.

Any feedback you may provide is greatly appreciated.

Thanks

Mike

 

[rbalex]

About all I can say at this point is, unless you have a control drawing, as required by Article 504, Section 504.10 that already tells you what you were doing is intrinsically safe, it isn't.