•
The RS-485 bus should be shielded 2 x 2 x 0,5mm² cable, as delivered by Alphatronics under
number 008654
•
The RS-485 bus must be connected through from point to point. All connected components are
connected in a straight line, without making star connections!
•
When the connected components obtain their power supply from the RS-485 bus, the incoming
power supply may not drop below 8,0 VDC in the worst possible condition (cut off mains voltage
and minimal battery voltage). Assuming a minimal battery voltage of 10V this makes a maximal
possible power loss of 2VDC over the bus cable. It is possible to run extra cable with thicker wires
for the power supply, when the power loss creates a problem.
When connecting the components in one straight line is not possible, you can create star connections.
However, the maximal distance for the cable decreases. How much it decreases depends on the situation.
When using star connections, we recommend keeping the total bus cable length below 500 meters.
The ohmic resistance of the RS-485 cable delivered by Alphatronics (008654) is about 10 Ohm for each 100
meters.
Attention:
There is NO shut-off resistor placed between the A and B lines!
AlphaVision NG installation manual Rev. 2.0 27-08-2003 Blz. 10/101
