Rockwell Automation 1797-Series ControlNet Ex Media Plannng Installation Manual - Manual (Page 29)

Publication CNET-IN003A-EN-P - January 2006
Plan a ControlNet Ex Media System 2-7
Estimate Fiber Media
Lengths The maximum length of a fiber media section for the 1797-RPFM
module is dependent on the quality of the fiber, number of splices,
and the number of connectors. The total attenuation for a cable
section must be less than 13.3 dB.
Typically, cable attenuation for a wavelength of 1300 nm is less than
1.5 dB/km.
Determine How Many Trunk
Terminators You Need You must use 75
Ω
trunk terminators equipped with intrinsically-safe
insulators (cat. no. 1797-XT) at the end of each segment in the
ControlNet Ex cable system.
500 m
(1640 ft)
250 m
(820 ft)
2 20
Number of Taps With One FLEX Ex Redundant ControlNet Barrier Module
Seg
m
ent
Lengt
h
m (f
t)
IMPORTANT
Avoid joining cable with connectors as much as
possible. Connectors can cause considerable
attenuation and limit the maximum length of your
system. Be sure to check the attenuation of each
cable sections after the cable is installed.
1797-XT
Intrinsically-safe Insulator