Dorset identification b.v. Reserves the rights to change
specifications without prior notice
13
5.2 Network communication via 2-wire RS485 interface.
The LID665A proximity decoders and the LID650A handsfree decoders can be used in the same 2-
wire RS485 network.
NOTES:
•
Use twisted pair cable.
•
Both decoders on the end of the bus (here unit 1 and 3) need a termination resistor. This
resistor is already available on the decoder and can be used by placing the solder-jumper on the
decoder board. The position of the solder jumper is shown in chapter 2.1 note
1)
& 2.2 note
1)
of this
manual.
•
One decoder on the end of the bus needs 2 fail-safe resistors (here unit 1). These 680 ohm
resistors are placed between line A and Gnd and line B and +5V.
LID665OEM decoders: resistor 1 between J1.2 and J2.3, resistor 2 between J2.4 and J2.5.
LID665BPv14 backplane: resistor 1 between J1.2 and J2.3, resistor 2 between J2.6 and J2.7.
LID650 decoders: resistor 1 between J6.3 and J8.1, resistor 2 between J6.4 and J6.5
•
The PC should not be placed at the end of the bus. When the PC is detached from the RS485
network, the termination resistor on the RS485 PC-card will be disconnected and the network will
not work.
•
The bus length may not exceed 1200 meters (4000ft).
•
Do not use branches from the bus to a decoder, but make the connection on the decoder itself.
The bus must go directly from decoder to decoder.
•
The maximum number of decoders on each bus is 31. Multiple RS485 busses can be used
with only one PC.
•
The PC software requires a RS485 PC-card or Converter with automatic data direction
control.
•
One decoder can be used for switching on an alarmsystem. All other decoders in the same
network can switch the alarm off when a valid transponder is read. See appendix A for more
information on using a decoder to switch the alarmsystem.
For connecting the RS485 bus to the PC card/converter please use the manual of this converter.
PC with RS485 Card
Unit 2
LID650
ANT610
Unit 3
LID665
ANT614
Unit 1
LID665
ANT614
7
5
0
+
5
V
7
5
0
G
n
d
Ground
RS485 B
RS485 A
