Menvier300
Before You Begin
Page 13
Table 1. Voltage Drop
Current
Drawn
Cable Length (Standard 7/0.2 alarm cable)
10m
20m
30m
40m
50m
60m
70m
80m
90m
100m
60mA
0.10V
0.19V
0.29V
0.38V
0.48V
0.58V
0.67V
0.77V
0.86V
0.96V
80mA
0.13V
0.26V
0.38V
0.51V
0.64V
0.79V
0.90V
1.02V
1.15V
1.28V
100mA
0.16V
0.32V
0.48V
0.64V
0.80V
0.96V
1.12V
1.28V
1.44V
1.60V
120mA
0.19V
0.38V
0.58V
0.79V
0.96V
1.15V
1.34V
1.54V
1.74V
1.92V
140mA
0.22V
0.45V
0.67V
0.90V
1.12V
1.34V
1.57V
1.79V
2.02V
2.24V
160mA
0.26V
0.51V
0.77V
1.02V
1.28V
1.54V
1.79V
2.05V
2.30V
2.56V
180mA
0.29V
0.58V
0.86V
1.15V
1.44V
1.73V
2.02V
2.30V
2.59V
2.88V
200mA
0.32V
0.64V
0.96V
1.28V
1.60V
1.92V
2.24V
2.56V
2.88V
3.20V
220mA
0.35V
0.70V
1.06V
1.41V
1.76V
2.11V
2.46V
2.82V
3.17V
3.52V
240mA
0.38V
0.79V
1.15V
1.54V
1.92V
2.30V
2.69V
3.07V
3.46V
3.84V
260mA
0.42V
0.83V
1.25V
1.66V
2.08V
2.50V
2.91V
3.33V
3.74V
4.16V
280mA
0.45V
0.90V
1.34V
1.79V
2.24V
2.69V
3.14V
3.58V
4.03V
4.48V
300mA
0.48V
0.96V
1.44V
1.92V
2.40V
2.88V
3.36V
3.84V
4.32V
4.80V
320mA
0.51V
1.02V
1.55V
2.05V
2.56V
3.07V
3.58V
4.10V
4.61V
5.12V
340mA
0.54V
1.09V
1.63V
2.18V
2.72V
3.26V
3.81V
4.35V
4.90V
5.44V
360mA
0.58V
1.15V
1.73V
2.30V
2.88V
3.46V
4.03V
4.61V
5.18V
5.76V
380mA
0.61V
1.22V
1.82V
2.43V
3.04V
3.65V
4.26V
4.86V
5.47V
6.08V
400mA
0.64V
1.28V
1.92V
2.56V
3.20V
3.84V
4.48V
5.12V
5.76V
6.40V
Reducing Voltage Drop - Method 1:
Double up the supply connections (12V and 0V),
which will halve the resistance on each core and
therefore halve the voltage drop. When using
Table 1 to calculate the expected voltage drop,
simply divide the voltage drop for a single core by
two.
Reducing Voltage Drop - Method 2:
Supply the detection devices from the Aux output
on separate cores. This is the preferred method of
reducing voltage drop as detectors generally
operate at lower voltages (9.5V). When using this
method, the bus cable must have at least two
spare cores.
Remote Power Supplies
When you cannot reduce voltage drops by
method 1 or 2, or the demand on the control unit
power supply exceeds its capacity (see Technical
Specifications
–page 33), you should install one or
more remote power supplies. The supply must
have a "floating zero volt rail" if connected to the
bus, otherwise an earth fault will occur.
Eaton’s
Security Business recommends the EXP-PSU.
When installing a remote power supply, fit it close
to the equipment it is powering.
Figure 19 shows the recommended method of
connecting a remote power supply.
Figure 19. Connecting Remote Power Supply Units
Control unit
Device 1
12V
0V
0V 12V
Bus
Device 2
Remote PSU
Device 4
Device 3
