One Power Supply (Middle-Connected) - Parker H Series Installation & Service Instructions Manual

4-12 Determine Power Requirements
TR
TR = terminating resistor T = T-Port tap
PT = PowerTap tap
Publication DNET-UM072C-EN-P - July 2004
Since the total current does not exceed the maximum allowable current, the
system will operate properly (0.65A ≤ 2.47A).
Results
IMPORTANT

One power supply (middle-connected)

The following example uses the look-up method to determine the
configuration for one middle-connected power supply. One middle-connected
power supply provides the maximum current capability for a single supply.
section 1
122m
(400 ft)
T T
D1 D2
1.25A
1.10A
D = device
1. Add each device's current together in section 1.
1.10 + 1.25 + 0.50 = 2.85A
2. Add each device's current together in section 2.
0.25 + 0.25 + 0.25 = 0.75A
3. Find the value next largest to each section's length to determine the
approximate maximum current allowed for each section.
Section 1 = 140m (2.14A)
If your application doesn't fit "under the curve", you may
either:
• do the full-calculation method described later in this
chapter, or
• move the power supply to somewhere in the middle of
the cable system and reevaluate per the following
section
power
supply
91m
91m
(300 ft) (300 ft)
49m
37m
(160 ft)
(120 ft)
PT
T
D3
0.50A
section 2
122m
(400 ft)
T T
D4
D5
0.25A
0.25A
T TR
D6
0.25A
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