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VIFB13 - 03/05
Operating voltage supply
3.15 AT
V
B
AC
10 AT
DC
0 V
Distance (cable length)
*) Operating voltage can be switched off separately
Fig. A/3: Cable length (L) and line resistance (R
9809b
Appendix A
Calculating with a formula
Proceed as follows:
1. Calculate the maximum current consumption
of the inputs and electronic components (I
as well as of the outputs/valves (I
2. Calculate the lowest voltage to be expected
on the power unit during operation (V
Take into consideration:
• the influence of load variation of the power
unit
• the fluctuations in the primary
mains voltage.
3. Enter the values in the appropriate formula.
The replacement circuit diagram and the
example explain the process.
Replacement circuit diagram
Valve
terminal
I
1
Pin 1
Pin 2
I
2
*)
Pin 3
I
0
L
).
2
).
Omin
V
Line
B
resistance
(incoming)
V
L1
R
R
V
L1
L2
L2
R
R
V
I1
I2
terminal
R
V
+ V
L0
L2
L1
Line
resistance
(returning)
0 V
L)
A-9
)
1
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