Mitsubishi Electric CC-Link-AnyWire Bitty Bridge User Manual page 20

(2) Description of calculation formulas 2) and 3)
(a) Vm: Supply voltage to bridge module
Voltage: 24VDC -10 to +15% (21.6 to 27.6VDC), Ripple 0.5Vp-p or less
Recommended voltage: 26.4V
(b) V(V): Voltage drop between lines
V(V) = Transmission cable supply current I (A)  Line resistance R ()
Line resistance R() = Line length (m)  Conductor resistance (/m)  2
• Line diameter 1.25  Conductor resistance 0.015/m
• Line diameter 0.75  Conductor resistance 0.025/m
(3) Calculation example
The example shows how to check whether the total length of 50m is sufficient for configuring the system with the
following conditions.
(a) Condition
Item
Non-isolated remote I/O module (input)
Connected load (three-wire sensor)
Diameter of transmission cable (DP, DN)
Power supply for the NZ2AW1C1BY
(b) Calculation result
Item
Calculation formula 1)
Calculation formula 2)
Calculation formula 3)
Based on the above calculation results of calculation formulas 1) through 3), system configuration is found
impossible.
However, changing the diameter of the connection cable and the power supply for the NZ2AW1C1BY enables
the system to be configured.
18
• Number of I/O points: 4 points
• Module current consumption: 29mA
• Number of modules: 12
• Three-wire sensor current consumption: 13mA
• Number of sensors: 4
• Power voltage: 24V 10%
Cable diameter: 0.75
Power voltage: 24V
(Ihin(A)  m) = I(A)  Maximum value of transmission cable supply current
(0.029 + (0.013  4))  12 = 0.972A  1A
 Satisfied
Vm(V) - V(V)  20V
24 - (0.972  50  0.025  2) = 24 - 2.43 = 21.57V  20V
 Satisfied
Vm(V) - V(V)  The lowest limit of the allowable voltage range for connected load
The lowest limit of the allowable voltage range for connected load = 24 - 24  0.1 = 21.6V
21.57V < 21.6V
 Not satisfied
Condition
Condition