57
© Carlo Gavazzi A/S
System Calculation
The two calculation examples below show how it is possible to determine the number of
sensors or the length of cable�
Calculation example 1: How to find the max cable length in a system
Example of a slave monitor with 100 sensors connected:
•
Current consumption of the sensor is: 20 mA max
•
Max voltage drop on the far end Sensor is 4�0 V (When using 28 V DC on the
GP3496 0005)
•
Cable resistance is 13 Ω/Km with the use of 1�5 mm
2
, (14-16AWG)
Max current in a system is 20 * 100 = 2�0 A
RS485
Server
Router
Moxa
Ethernet/
RS485
Converter
Server Room
Cabinet 1
Cabinet 2
Cabinet 3
Cabinet 4
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
Carpark Master Module
GP3496 0005
Carpark Master Module
GP3496 0005
Carpark Master Module
GP3496 0005
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
1 2 3 4 5 6 7 8
21 22 23 24 25 26 27 28
1 2 3 4 5 6
Carpark Master Module
GP3496 0005
Carpark Master Module
GP3496 0005
Carpark Master Module
GP3496 0005
Fig. 70: Extended wiring