Rockwell Automation 1797-Series ControlNet Ex Media Plannng Installation Manual - Manual (Page 27)

Publication CNET-IN003A-EN-P - January 2006
Plan a ControlNet Ex Media System 2-5
requirement. The maximum allowable total length of a segment is
1,000 m (3,280 ft) with two taps connected. Each additional tap
decreases the maximum length of the segment by 16.3 m (53.4 ft). The
maximum number of taps allowed on a segment is 48 with a
maximum length of 250 m (820 ft).
Figure 2.2 ControlNet Single Media Derating Curve
An allowable total length of RG-6 cable segment in your application
can be determined by using the equation below. Each additional tap
decreases the maximum length of the segment. The maximum
number of taps allowed on a segment is 48. Each additional tap
decreases the maximum length of the segment.
IMPORTANT
The derating curve is applicable only when the cable
meets ControlNet attenuation specifications.
1000 (3280)
750 (2460)
500 (1640)
250 (820)
2 16 32 48
Maximum Allowable Segment Length
for FLEX Ex on ControlNet =
1000 m (3280 ft) - 16.3 m (53.4 ft) X
[Number of Taps - 2]
Number of Taps
S
eg
m
en
t
Le
ng
th
m
(f
t)
30014-m
EXAMPLE
If your segment requires 10 taps, the maximum
segment length is:
1000m (3280 ft) - 16.3 m (53.4 ft) x [10 - 2]
1000m (3280 ft) - 130.4 m (427.7 ft)= 869.6 m
(2852.3 ft)
IMPORTANT
This equation applies when the cable does not meet
ControlNet attenuation specifications.
Maximum Allowable Segment Length of Cable =
(20.29 db - Number Of Taps in Segment *.32 db)
Cable Attenuation @ 10 MHz per 304 m (1000 ft)
Note: Cable attenuation is defined as the signal loss measured at 10 MHz per
304 m (1000 ft) of cable. Cable attenuation for ControlNet Ex cables is listed
in the ControlNet Ex Media Component List, publication AG-PA002.
X 304 m (1000 ft)