ComAp IM-NT, Справочное руководство

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InteliMains
NT
, SW version 3.0
InteliMains-NT-BTB-3.0-Reference Guide.pdf,
©ComAp – June 2013
25
3.11 CAN and RS485 bus wiring
The wiring of the CAN bus communication should be provided in such a way that the following rules
are observed:

The maximum length of the CAN bus depends on the communication speed. For a speed of
250 kbps, which is used on the CAN1 bus (extension modules, ECU) and CAN2 bus if it is
switched to 32C mode, the maximum length is 200 m. If the CAN2 bus is switched to 8C mode
the speed is 50 kbps and the maximum length is 800 m.

The maximum length of the RS485 bus is 1000 m

The bus (CAN and RS485) must be wired in linear form with termination resistors at both
ends. No nodes are allowed except on the controller terminals.
N
OTE
:
A termination resistors at the CAN and RS485 are already implemented on the PCB. For
connecting, close the jumper near the appropriate CAN or RS485 terminal. For more
information on jumper settings please refer to the section
3.1.4 Jumper setting .

Use a cable with following parameters:
Cable type Shielded twisted pair
Impedance
120 Ω
Propagation velocity
≥
75% (delay
≤
4.4 ns/m)
Wire crosscut
≥
0.25 mm
2
Attenuation (@1MHz)
≤
2dB/100 m
CAN
AND
RS485
BUS TOPOLOGY
N
OTE
:
See the website www.can-cia.org for information about the CAN bus, specifications, etc.