CAN bus Cables and Connectors

 

 

Cable Length, Wires and Terminators

The CAN bus cable contains normally 5 wires.
The CAN-L, CAN-H and Gnd Wire start on one end of the total network,
a terminator of 120 Ohm is connected between CAN-L and CAN-H.
The cable is connected form CAN node to CAN node, normally without or short T connections.
On the other end of the cable again a 120 Ohm terminator resistor is connected between the CAN lines.

In many CAN systems like DeviceNet Two power lines (in the CAN cable) are also connected to each node.

The cable length depend on the selected band rate on the bus: how higher the speed, how shorter the bus.

 

Bus speed

Cable type

Cable resistance/m

Terminator

Bus Length

50 kbit/s at 1000 m

0.75 ...0.8 mm2
AWG18

70 mOhm

150 ... 300 Ohm

600 .. 1000 m

100 kbit/s at 500 m

0.5 ... 0.6 mm2
AWG20

< 60 mOhm

150 ... 300 Ohm

300 ... 600 m

500 kbit/s at 100 m

0.34 ...0.6 mm2
AWG22, AWG20

< 40 mOhm

127 Ohm

40 ... 300 m

1000 kbit/s at 40 m

0.25 ...0.34 mm2
AWG23, AWG22

< 26 mOhm

124 Ohm

0 ... 40 m

In the devices of CD Systems the slope control of the bus driver is active for baud rates 10 Kb, 20 kb and 50 kb.


EMC ferrite beads

  • The CAN bus cable is a 4-wire un-shielded cable, the special bus driver chip in the CAN Node protect the Node from distortion, however the CAN cable could be a transport medium for all kinds of HF signals, by placing a ferrite beads over the CAN bus cable close the each connector can prevent this misuse.

RJ10 connector  Cable part

Used by: CANopen

Type: RJ10

 

Pin

Description

Colour

1

V-

Black

2

CAN_L

Red

3

CAN_H

Green

4

V+

Yellow

Cable specification:

The 4- wire telephone cable comes with a resistance of 142 Ohm / 1000 mtr.
The cable capacity is aprox. 150 pF / mtr.  

 


RJ11 and RJ12 connector  Cable part

Used by: CANopen

Type: RJ11 ,RJ12

 

Pin

Description

Colour

1
nc -

2

V-

Black

3

CAN_L

Red

4

CAN_H

Green

5

V+

Yellow

6

nc -

Cable specification:

The 4- wire telephone cable comes with a resistance of 142 Ohm / 1000 mtr.
The cable capacity is aprox. 150 pF / mtr.  


9-pole sub-D connectors Female cable part

Used by: CANopen 

Type: 9-pole sub-D

 

Pin

Description

Description

 

1

 

reserved

2

CAN_L

CANbus L

3

V-

CAN gnd

4

  

reserved

5

(CAN_shld)

Optional CAN shield

6

(gnd)

Optional CAN gnd

7

CAN_H

CANbus H

8
  

reserved error line

9

V+

CAN supply

Connectors on devices have male contacts.

CAN bus connection diagram


Hand wired connectors Female cable part

Used by: DeviceNet

Type: Screw type Weidmuller

 

Pin

Description

Color

 

1

V-

Black

2

CAN_L

Blue

3

Drain

Bare

4

CAN_H

White

5

V+

Red

Connectors on devices have male contacts.


Sealed mini style connectors

Used by: DeviceNet

Type: ANSI/B93.55M-1981

 

Pin

Description

Color

 

1

Drain

Bare

2

V+

Red

3

V-

Black

4

CAN_H

White

5

CAN_L

Blue

Connectors on devices have male contacts.


Sealed Micro style connectors

Used by: DeviceNet

Type: Lumberg style RKT 5-56/xm or equivalent

 

Pin

Description

Color

1

Drain

Bare

2

V+

Red

3

V-

Black

4

CAN_H

White

5

CAN_L

Blue

Connectors on devices have male contacts.


Micro style connectors

Used by: SDS

Type: Female round

 

Pin

Description

Color

 

1

V+

Brown

2

V-

Blue

3

CAN_L

White

4

CAN_H

Black

 


Sealed mini style connectors

Used by: SDS

Type: Female round

 

Pin

Description

Color

 

1

Shield

Bare

2

V+

Brown

3

V-

Blue

4

CAN_H

Black

5

CAN_L

White

 


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