User manual

Publication CNET-UM001C-EN-P - November 2005
Determine Your ControlNet Media Requirements C-11
Determine How
Many Trunk Terminators
You Need
You must use 75Ω trunk terminators (cat. nos. 1786-XT and 1797-XT) to
terminate each segment for the ControlNet cable system. You need two XT
terminators per segment because you need one for each end of the segment.
After you have determined how many segments will be in your network,
multiply this number by two to figure out how many terminators you will need
for your network.
Be sure to cover the exposed metal using the intrinsically safe sheath provided
with each terminator in order to comply with intrinsic safety standards. The
1786-XT and 1797-XT trunk terminators are the same mechanically and
electrically. You can mix these terminators in non-intrinsically safe
environments. However, you must only use the 1797-XT terminators in
intrinsically safe environments to maintain your application’s Ex rating.
Configure Your Link With Repeaters
When you configure your link using repeaters, you can install them in one of
three ways:
You Can Install
Repeaters In
Use a Maximum of See
Series 20 repeaters Install Repeaters In Series
Parallel 48 repeaters Install Repeaters In
Parallel
A combination of series
and parallel
20 repeaters in series; 48
repeaters in parallel
Install Repeaters In A
Combination Of Series
And Parallel
IMPORTANT
A repeater can be connected to a segment at any tap
location.
Intrinsically Safe Sheath
(1797-XT Only)
1786-XT
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