CAN (Controller Area Network)
There are two channels fully dedicated to CAN communications on the 50 pin hardware. One channel
routed to the primary processor only, and the other channel is routed to both the primary and secondary
processors.
There is one channel fully dedicated to CAN communications on the 24 pin hardware. This channel is
routed to both the primary and secondary processors.
Baud rate
Up to 1 MBps
Termination
No internal termination
CAN system design
All PLUS+1
®
modules have CAN ports that conform to CAN 2.0B specifications, including CAN shield.
W
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
Machine performance may be impaired if CAN communications are disrupted by electrical fields in excess
of 30 V/m between 20 and 30 MHz. To prevent potential unintended machine movement and to meet
EMC requirements, a shielded CAN bus must be used to achieve 100 V/m immunity.
Specifications for terminating resistor
Each end of the main backbone of the CAN bus must be terminated with an appropriate resistance to
provide correct termination of the CAN_H and CAN_L conductors. This termination resistance should be
connected between the CAN_H and CAN_L conductors.
Specifications
Description
Units
Minimum
Maximum
Nominal
Comment
Resistance
Ω
110
130
120
Minimum power dissipation 400 mW
(assumes a short of 16 Vdc to CAN_H).
Inductance
µH
1
Notes on CAN Bus installation
Total bus impedance should be 60 Ω.
The CAN transceiver will be damaged by any voltage outside of allowable range, (-7 to +36 Vdc), even
with a very short pulse.
If using shielded cable, the shield must be grounded to the machine ground at one point only; preferably
at the mid-point of the CAN bus. Each PLUS+1
®
module CAN shield pin must be connected to the cable
shield.
Expansion module CAN Bus loading
System designers incorporating PLUS+1
®
expansion modules in their applications should be aware of
PLUS+1
®
CAN bus loading and controller memory usage during system design. Each expansion module is
associated with a PLUS+1
®
controller and uses part of the controller's memory resources for inter-module
communications. The table below can be used to estimate system CAN bus loading and the memory
impact of I/O modules on their associated controller.
Technical Information
PLUS+1 SC0XX-1XX Controller Family
Controller Area Network specifications
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©
Danfoss | June 2016
L1415500 | BC00000235en-US0201