Weidmuller SAI Active Universal Pro Series, Руководство пользователя

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Project Planning with the Universal Pro
18 5663600000/1.4/09.09
Voltage drop / max. expansion
The maximum expansion of the sub-bus system de-
pends on four factors:
•
The number of stations
•
The distance between stations
•
The current load of each participant and there in-
puts
•
The resistance of the wires in use
The following formula results:
Voltage drop of the line =
current consumption of module x (line resistance x
line length x 2)
Total voltage drop =
voltage drop of line 1 + voltage drop of line 2 + volt-
age drop of line x
Voltage on last module =
Supply voltage to gateway I/O - 0.9V - total voltage
drop
Result:
When voltage to last module is greater then 18V DC
= Okay
When voltage to last module is less than 18V DC =
Not okay
We have made available a software tool to help you
calculate the residual current and voltage drop. It
can be downloaded from the Weidmueller home-
page at www.weidmueller.com.
3.3 An example - calculation of
power supply
A sub-bus system should be set up for 45 sensors
and 14 actuators. The extension distance is 30 m.
The following modules have been selected:
1 x 1938550000 Gateway IO Module 16DI M12
6 x 1938610000 Extension IO Module 8DI M12
2 x 1938640000 Extension IO Module 8DI/DO M12
1 x 1938680000 Extension I/O Module 8DO M12 2A
All sensors consume 10 mA current each.
No. Cat. No. Current for module Current for sensors Total current
1 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
2 1938680000 50 mA 50 mA
3 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
4 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
5 1938640000 50 mA 4 x 10 mA = 40 mA 90 mA
6 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
7 1938640000 50 mA 4 x 10 mA = 40 mA 90 mA
8 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
9 1938610000 50 mA 6 x 10 mA = 60 mA 110 mA
Table 3 Current consumption of the modules