Can Interface - Baldor MotiFlex e100 Installation Manual

5.7 CAN interface

The CAN bus is a serial based network originally developed for automotive applications, but now
used for a wide range of industrial applications. It offers low-cost serial communications with very
high reliability in an industrial environment; the probability of an undetected error is 4.7x10
It is optimized for the transmission of small data packets and therefore offers fast update of I/O
devices (peripheral devices) connected to the bus.
The CAN protocol only defines the physical attributes of the network, i.e. the electrical,
mechanical, functional and procedural parameters of the physical connection between devices.
The higher level network functionality on MotiFlex e100 is defined by the CANopen protocol, one
of the most used standards for machine control.
5.7.1 CAN connector
5
1
5.7.2 CAN wiring
A very low error bit rate over CAN can only be achieved with a suitable wiring scheme, so the
following points should be observed:
The two-wire data bus line may be routed parallel, twisted and/or shielded, depending on
H
EMC requirements. Baldor recommend a twisted pair cable with the shield/screen
connected to the connector backshell, in order to reduce RF emissions and provide immunity
to conducted interference.
The bus must be terminated at both ends only (not at intermediate points) with resistors of a
H
nominal value of 120 Ω. This is to reduce reflections of the electrical signals on the bus,
which helps a node to interpret the bus voltage levels correctly. If the MotiFlex e100 is at the
end of the network then ensure that a 120 Ω resistor is fitted (normally inside the D-type
connector).
All cables and connectors should have a nominal impedance of 120 Ω. Cables should have
H
a length related resistance of 70 mΩ/m and a nominal line delay of 5 ns/m.
5-22 Input / Output
Location CAN (top panel)
Mating connector: 9-pin female D-type
Pin Name
1 -
2 CAN-
3 CAN GND
4 -
5 Shield
9
6 CAN GND
7 CAN+
6
8 -
9 CAN V+
Description
(NC)
CAN channel negative
Ground/earth reference for CAN signals
(NC)
Shield connection
Ground/earth reference for CAN signals
CAN channel positive
(NC)
CAN power V+ (12-24 VDC)
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MN1943