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The following illustration shows how a module is
connected via the clamp socket connector as a
pass module. In this case, the CAN-bus cable lead-
ing to the next module must be connected to a row
of the clamp socket.
The correct terminal assignment must be ensured.
Module connection with spring clips
(pass module)
The cores must be firmly connected to the spring
clip terminal. This can be checked by pulling the
cores lightly.
Colour coding for cables of the type
LiYCY 2x2x0.5 mm² (Article-No. 339 0001)
PIN no.
Clip no.
Wire colour
Function
1
green (GN)
CAN-High
2
yellow (YE)
CAN-Low
3
white (WH)
+24 VDC
4
brown (BN)
GND 24 V
4.3 Termination of the CAN-Bus
For a CAN-bus, it is important that the single
elements of the CAN-bus chain are correctly termi-
nated. Physically, this means that the two ele-
ments at the end of the CAN-bus chain (final ele-
ments) must have a terminating resistor of
120 Ω each. This prevents signal reflections and
interference.
Elements within a CAN-bus chain (pass elements)
must not have a terminating resistor.
Exemplary schematic representation
of the CAN-bus structure
The terminating resistor is switched on and off
with a DIP switch. At modules, this DIP switch is
located next to the connection terminals of the
sensors in the module housing and is labelled
"Termination".
The terminating resistor is switched on when the
DIP switch is in position "ON".
It is switched off in the "OFF" position.
The BlueBox itself can also be used to switch on
and off the terminating resistance.
Since the BlueBox is located at the end of the CAN-
bus chain in the majority of installations, the Blue-
Box is terminated at the factory, i.e. the terminat-
ing resistor is switched on.
If the BlueBox is located within a CAN-bus chain,
the termination of the BlueBox must be switched
off.
Termination of a BlueBox
see
3.7 CAN-bus Termination at the BlueBox
Termination at an active CAN repeater
see
5 Active CAN Repeater
Termination OFF
