MD 5850
Installation Manual
4
EXTERNAL CABLE INTERFACE
4.1 Cable
dimensions
Data (RS422 or 10Mbit Ethernet):
2 twisted pairs with outer screen (Max 150m)
Data
(RS232):
2
pair
0,5
mm
2
(Max 10 meters)
Data through optical 10Mbit Ethernet:
2 optical fibres. (Max 2 km)
Data through coaxial 10Mbit Ethernet:
1 coax cable (Max 150 m)
Power Supply 24VDC (48VDC):
3 wires 0.8 mm
2
(Max 150m) for +VDC and -
V DC
Power Supply 12VDC:
3 wires 0.8 mm
2
(Max 10m) for +VDC and -
V DC
4.2 Circular
connector
Connecting Power
To be able to use a cable which is 150m long with 0.8 mm
2
wire size, it is necessary to use at
least 3 wires for both minus (-) and plus (+) 24V supply to be sure that the voltage does not drop
below 20V at the input of the DC-DC converters.
The connection of the cable to the circular connector is shown in fig.5.1.1. The cable should
have at least 10 wires including two twisted pairs for data transfer. The minimum Supply
Voltage depends on how large voltage drop there is through the cable. As mentioned before the
input voltage to the MultiReader must not be below +18V (Preferable not below +20V) with
+24V power supply. As an example the cable wires for the VDC must have a square of 0.8mm²,
if the cable has a length of 150m.
Because of “in rush current” when turning on the power, the roadside supply should be able
to deliver 100W at 24VDC (48VDC or 12VDC).
+
+
-
TX
-
+
RS422
RX
RS422
A
B
C
D
E
F
G
H
I
J
-VDC
+VDC
DATA
ROADSIDE
CABLE
10 pin circular connector
24V
To RS422 interface
Connector
side
-
Fig.5.1.1 Power and data cable interface to circular connector.
Connecting Data
The data communication is performed through twisted pairs. Transmit (TX) signals on pin G
&H and receive signals (RX) on pin F&E referred to the RS422 circular connector interface at
the MultiReader.
The maximum length of data transmission on twisted pairs depends of the cable category.
Category 5 is recommended. NB! The TX at the connector side is coupled to the RX at the
Q-Free
®
ASA
645-054-1999 rev.4
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