TCP/IP
50m
max.
50m
max.
50m
max.
Switch
CONNECTING BIOMETRIC READERS WHEN ALL THE CONTROLLERS HAVE TCP/IP COMMUNICATION
When all the controllers are connected via TCP/IP, then the RS485 network becomes local (from Reader 1 to the Controller then to
the Reader 2).
Connect the readers directly to the Rs485 terminals in each controller.
If the distance Reader-Controller is high (50meters) and if the communication with the reader can not be established, then
terminate the RS485 network by closing the jumper in the EWS Controller or as described in chapter 4.
NOTE: This is recommended configuration when you have multiple biometric
readers in the same network. In this configuration, NO TERMINATION resistors are
required.
When all the controllers have TCP/IP communication the biometric readers are easily wired.
When the controllers have RS485 communication, it is difficult to maintain the daisy chain of
the RS485 network. Wiring the biometric readers in that formation is a challenge. See the
schematic diagram bellow.
RS485
RS485
5.3 RS485 TUNING
- Terminate both ends of the line with 120 Ohm resistor. If end of line is EWS, use built in resistor (120 ohm) by closing
the jumper.
- If the communica on is not established and stable, use the external resistors provided in the hardware kit.
When using CAT 5 compa ble cable, in most of the cases, termina on made with 50 Ohm external resistor or combina on
of 50 Ohm external and termina on resistor from the EWS (120 Ohm) should be the solu on.
RS485 Termina on resistors:
RS485
1 km max / 32 Units (EWS + Biometric Readers)
TCP/IP
gnd
gnd
Stub
max. 5m
Jumper for
RS485 termination
50 ohm
50 ohm
6
