Rockwell Automation 1794-APBDPV1 FLEX I/O PROFIBUS Adapter User Manual - Manual (Page 111)

Publication 1794-UM064B-EN-P - May 2014
Apply FLEX I/O Modules 99
Once Rtotal is known, you must determine the actual cable resistance that can be
accommodated. This is the difference between Rtotal and the module internal
source and sense resistances: Rcable=440-273-10=157
Ω.
Rcable is used to determine the wiring length allowed between the module and
the transmitter:
Note, the 2 in the denominator of the equation is necessary to account for the
resistance of both cable conductors (signal source + and signal and return).
Chapter Summary In this chapter you learned how to apply the FLEX I/O analog modules.
Cable_length =
157
2*0.1
= 785 m