13
LANGER
EMV-Technik
DE-01728 Bannewitz
[email protected]
www.langer-emv.com
OB 100 set
8.5. Signal Transmission
– Optical Connection
The double optical fiber is plugged into the optical fiber input and the optical fiber output (Figure 1)
and fixed with both knurled nuts. The ends of the two individual optical fibers are cut to different
lengths and can thus be correctly assigned:
The slightly longer optical fiber is always connected to the optical input, the slightly shorter one
to the optical output (see marking on the Opto-Box 100, long and short arrow).
The maximum length of the optical fiber is 20 m. In practice, however, in CAN operation at a
transmission rate of 1 Mbit/s, the delay of the optical receivers results in a reduction of the
permissible length to 6-10 m (depending on the edge steepness of the signal and the reaction time
of the other connected CAN nodes), since otherwise the acknowledge bit is no longer recognized
in time by the transmitter.
If the Opto-Box 100 is only used for "listening" to an existing CAN connection between other
nodes, this restriction does not exist.
