Rockwell Automation 1788 NetLinx Media Checker Users Manual - Manual (Page 32)

32 Calculating the Distance to a Short
1788-UM002A-US-P – April 2000
Table 12. Measured Tap Lengths for ControlNet
Cables (cont.)
Number
of Taps Terminated Tap* Unterminated Tap
36 281 ft (85.5 m) 155 ft (47 m)
37 289 ft (88 m) 159 ft (48.5 m)
38 296 ft (90.5 m) 163 ft (50 m)
39 304 ft (92.5 m) 168 ft (51 m)
40 312 ft (95 m) 172 ft (52.5 m)
41 320 ft (97.5 m) 176 ft (53.5 m)
42 328 ft (100 m) 181 ft (55 m)
43 335 ft (102 m) 185 ft (56.5 m)
44 343 ft (104.5 m) 189 ft (57.5 m)
45 351 ft (107 m) 194 ft (59 m)
46 359 ft (109.5 m) 198 ft (60.5 m)
47 367 ft (111.5 m) 202 ft (61.5 m)
48 374 ft (114 m) 206 ft (63 m)
* Terminated with 1786/1797-TCAP
Calculating the Distance to a Short
Depending on the type of short on a cable, the
MediaChecker may or may not be able to determine the
distance to the short. If the MediaChecker cannot report
the distance, you can use the information in this section
to calculate the distance to the short.
You can also use this information to calculate the
approximate length of a terminated cable.
The MediaChecker reports information on shorts and
terminated cables as follows:
Short across a data pair: The MediaChecker measures
the resistance of the short, then displays the distance to
the short based on the resistance.
Short across a power pair or from a power wire to a
data wire: The MediaChecker measures and displays the
resistance of the short. You can use the resistance value
to calculate the distance to the short.