Festo SEC-AC-305-CO, Manual

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2. Cabling and pin assignment
2−9
Festo P.BE−SEC−AC−CO−E N en 0802a
2.7 CAN bus cabling
Caution
Please respect carefully the following information and
notes for the cabling of the controller to get a stable and
undisturbed communication system. A non professional
cabling can cause malfunctions of the can bus which hence
the controller to shutdown with an error.
2.8 Cabling notes
The can bus offers an easy and safe way to connect all parts
of a plant. As condition all following instructions have to be
respected carefully.
Fig.2/5: Cabling (schematically)
·
All nodes of a network are principally connected in series,
so that the CAN cable is looped through all controllers
(see Figure 2.2).
·
The two ends of the CAN cable have to be terminated by a
resistor of 120 ± 5%. Please note that such a resistor is
often already installed in CAN cards or the PLC.
·
For cabling shielded cable with exactly two twisted pairs
have to be used.
One twisted pair is used for CAN−H and CAN−L.
One twisted pair is used commonly for CAN−GND.