IDTECK FINGER006SR, Быстрое руководство по установке

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※ FINGER006 SERIES QUICK INSTALLATION GUIDE
8
②
Reader (Power and Data)
FINGER006 Controller
Belden #9512, 22 AWG
4 conductor, shielded
Belden #9514, 22 AWG
8 conductor, shielded
③
Door Contact
Exit Button
Sensor Input
Input Controller
Belden #9512, 22 AWG
4 conductor, shielded
Belden #9514, 22 AWG
8 conductor, shielded
④
Door Lock, Alarm Device
Lock (Alarm) Controller
Belden #9409, 18AWG
2 conductor, unshielded
⑤
RS232 Cable
Belden #9829, 24 AWG
2-twisted pair, shielded
Converter Host P.C.
⑥
RS485 Cable
Belden #9829, 24 AWG
2-twisted pair, shielded
Controller Converter
Controller Controller
Controller FINGER006
FINGER006 FINGER006
FINGER006 Converter
RS422 Cable
Belden #9830, 24 AWG
3-twisted pair, shielded
Controller Converter
Controller Controller
Controller FINGER006
FINGER006 FINGER006
FINGER006 Converter
*
Thicker wires are necessary if the connected reader consumes a higher current.
4.2 Check Point during Installation
4.2.1 Termination Resistor
Termination resistors are used to match impedance of the network to the impedance of the transmission line being
used. When impedance is mismatched, the transmitted signal is not completely absorbed by the receiver and a portion
of signal is reflected back into the transmission line.
The decision whether or not to use termination resistors should be based on the cable length and data rate used by
the communication system.
For example, if you use 9,600 baud rate and 1,200m length of cable, the propagation velocity of cable is 0.66 x speed
of light (This value is specified by the cable manufacturer), if we assume the reflections will damp out in three round
trip up and down the cable length, the transmitted signal will stabilize 18.6us after the leading edge of a bit. Since the
data bit is captured in the middle of the bit which is approximately 52us after the leading edge of a bit. The reflection
stabilizing time 18.6us is much before the center of the bit therefore the termination resistors are not required.
However, if you install the cable to maximum length, the impedance of cable and network is mismatched and the
transmitted signal is overlapped by the reflected signal. In this case, it is recommended to add termination resistors to
the end of the receiver lines. A 120
Ω
resistor can be used for termination resistor in parallel between the receiver
lines “A” and “B” for 2 wires RS485 system or “RX+” and “RX-” for 4 wires RS422 system. A termination resistor of less
than 90
Ω
should not be used and no more than 2 terminations should be used in one networking system.