CP3 version 3003
60
Calculation
If you are searching for different installation methods, please follow the calculation examples below.
For maximum 90 sensors connected to a CMCG and maximum 50 sensors in a Line.
Resistance in 1.5 mm
2
wire:
13 ohm/km
Current consumption in sensor:
28 mA
Maximum current in a lane is 28 * 90 =
2.52 A
The SBP2MCG324 has a maximum output current of 2.6 Amp.
A 25 % duty cycle is worst case scenario. This is because no outputs are used on the Dupline® when only
carpark sensors are used. This means we have 125 % current (pulsating) from the cabinet to the first
sensor.
We accept a maximum voltage drop of 3.5V on the Dupline® bus, from the cabinet to the last sensor in the
line. Because the D-wire is a ”common wire” for both Dupline® and the 28V supply, the calculation is as
follows:
2’nd degree equation:
0.5*S*X²+X*L-7216=0
X = Number of sensors
S = Length between the sensors
L = The distance from cabinet to first sensor in line
This formula can be used to calculate the above mentioned unknown factors in a carpark line. Please find
the calculation spreadsheet named “cp3” on
http://www.productselection.net/MANUALS/UK/cp3_manual.pdf