IDTECK LX006, User Manual

Page: 19 / 57

p.14 CHECK POINTS BEFORE INSTALLATION
1.2 RECOMMENDED CABLE TYPE AND PERMISSIBLE LENGTH OF CABLE
No Description Cable specification Maximum dist
ance
1
LX006/SR Power (DC+12V)DC Power -> LX006
/SR
Belden #9409,18 AW
G
2 conductor, unshiel
ded
30m
*2
1
RS232 Cable converter->Host P.C. Belden #9829, 24 A
WG
2-twisted pair, shield
ed
15m
3
RS485 CableLX006 -> LX006LX006 -> Convert
er
Belden #9829, 24 A
WG
2-twisted pair, shield
ed
1,200m
1.3 READER CONNECTION
If you install the reader in a long distance between the ACU and the reader, you should be a
ware there could be voltage drop between ends of GND wire. For example, if you connect a
reader with 100mA current consumption at 100m distance (assume to using DC resistance
of cable of 100Ω/100m) and the reader power is supplied from the ACU, the voltage drop o
f the GND wire will be 1V. In this case, the Wiegand data signal cannot be measured lower t
han 1V.
The most of ACU is capturing the signal by the voltage level of data input. 1V is the critical p
oint whether the ACU read the data logic “1” or logic “0” therefore the reader output cannot
be read correctly from the ACU.
There will be two methods to reduce the voltage drop and ACU can read data correctly.
 Reduce the DC resistance of GND wire;
Using thick cable or add more wires to GND wire in parallel. If you connect 4 wires
in parallel for GND, the DC resistance of GND wire will be reduced to 1/4 of single
wire.
 Use separate power for the reader;
1 Thicker wires are required if you connect the reader with high current consumption.