Mitsubishi A1SJH User Manual page 73

6. BASE UNIT AND EXTENSION CABLE
(4) Examples
A1S38B
A1S03B (0.021 Ω)
(a) Calculation of voltage drop of the main base unit
Vk = 0.007 × {0.32 + 0.05 × (9 + 8 + 7 + 6 + 5 + 4 + 3 + 2) + (0.27 × 8) ×
9} = 0.15372
(b) Calculation of voltage drop of the extension base unit
Vz = 0.006 × 0.27 × (8 + 7 + 6 + 5 + 4 + 3 + 2 + 1) = 0.05832
(c) Calculation of voltage drop in the extension cable
Vc = 0.021 × (0.27 × 8) = 0.04536
(d) Voltage at the receiving end
5.1 - 0.15372 - 0.05832 - 0.04536 = 4.8426 (V)
Since the voltage at the receiving end is more than 4.75 V, the system
can be put into operation.
(5) Minimizing the voltage drop
Try the following measures to minimize the voltage drop :
(a) Change the positions of modules.
Install the modules of the main base unit from slot 0 in descending order
of current consumption. Install modules with small current consumption
in the extension base units.
(b) Connect the base units in series.
By connecting the base units in series (connecting an extension cable to
the left side of a main base unit, see Section 8.4.2), the voltage drop of
the main base unit can be minimized. But when a long extension cable
is used for this connection, the extension cable may cause a larger
voltage drop than that of the main base unit. In such case, calculate the
voltage drop as described in (3).
(c) Use a short extension cable.
The shorter the extension cable, the lower and the smaller its voltage
drops. Use extension cables that are as short as possible.
A1S58B
6 - 6
MELSEC-A