Manual
VEK S4
FEIG ELECTRONIC GmbH
03/09
17
4.5.2
RS485 interface bus termination
+5V
GND
470
Ω
470
Ω
120
Ω
120
Ω
. . . . . .
Station
Typical wiring of the RS485 interface
The shown resistors are mounted inside the detector and switch able by the help of the DIP-switches
DIP switch
Description
5
470
Ω
-Pull-up resistor on RS485 B+
6
470
Ω
-Pull down resistor on RS485 A-
7
Bus termination 120
Ω
between RS485 B+ and A-
The RS485 bus must be terminated on the front end (control device or repeater) and back end (last detector)
with a 120
Ω
resistor. Set DIP switch 7 to ON in the last detector.
In addition the two RS485 signal lines B+ and A- must be connected once to 5V resp. to GND with a 470
Ω
resistor each. If this has not been done on the control device or repeater, the circuit can be activated on the
last detector using DIP switches 5 and 6.
As shipped the DIP switches are in the ‚OFF‘ position.
4.5.3
CANopen bus termination
CAN High
120
Ω
120
Ω
. . . . . .
CANopen devices
CAN Low
DIP switch
Description
8
Bus termination 120
Ω
between CAN-High and CAN-Low
The CAN bus must be terminated on the front end (control device or repeater) and back end (last detector)
with a 120
Ω
resistor. Set DIP switch 8 to ON in the last detector.
