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BASE UNIT AND EXTENSION CABLE6.
(4) Calculation examples
(a) Calculation of voltage drop on the main base unit
(b) Calculation of voltage drop on the extension base unit
V
Z = 0.006 0.27 (8+7+6+5+4+3+2+1) = 0.05832
(c) Voltage drop on the extension cable
V
C = 0.021 (0.27 8) = 0.04536
(d) Verification of the receiving port voltage
5.1-0.15358-0.05832-0.04536=4.84274(V)
Since the receiving port voltage is more than 4.75V, the above system is usable.
(5) To reduce the voltage drop
The following methods are effective to reduce the voltage drop.
(a) Change the installing position of the module
Install the modules with high current consumption in order starting from slot 0 of
the main base unit.
Install modules with low current consumption to the extension base unit.
(b) Connect the base units in series
By connecting base units in series (connecting the extension cable to the left
side of the main base unit. Refer to this section (2), the voltage drop on the main
base unit can be ignored.
If the extension cable is long, however, the voltage drop through the cable may
be larger than that on the main base unit. Therefore, calculate the voltage drop
according to (3).
(c) Use a shorter extension cable
The shorter the extension cable is, the smaller the resistive value and the
voltage drop become.
Use the extension cable as short as possible.
V
K= 0.007 {0.3 + 0.05 (9 + 8 + 7 + 6 + 5 + 4 + 3 + 2) + (0.27 8) 9} = 0.15358
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