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DIP switch on position „ON“,
the termination resistor is switched on.
The device is a final module.
DIP switch on position „OFF“,
the termination resistor is switched on.
The device is a pass module.
4.4 Checking the Termination
In order to ensure correct functioning of the CAN-
bus, the correct termination of the final elements
must be ensured.
For this you need a multimeter to measure the
resistance between CAN-High and CAN-Low.
The measurement can be performed on any ele-
ment within the CAN-bus system.
The easiest way to take the measurement is at the
openings below the clamp sockets (see next col-
umn).
Make sure that all elements of the CAN-bus
chain are voltage free.
The measurement procedure is described below:
Measure the resistance between CAN-High and
CAN-Low as shown in the figures below.
The measured resistance should be between 55 Ω
and 70 Ω. The following deviations can be as-
sumed to be caused by the following causes of
error:
0 Ω
Short-circuit in the line
< 55 Ω
More than two elements terminated.
120 Ω
Only one element is terminated.
(e.g. only the BlueBox is terminated)
>120 Ω
No element is terminated
or broken cable.
Correct termination
Termination
CA
N
- B
us
OFF ON
1 CAN - H
2 CAN - L
3 +24V
4 24V GND
1
2
3
4
Termination
CA
N
- B
us
OFF ON
1 CAN - H
2 CAN - L
3 +24V
4 24V GND
1
2
3
4
