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Correctly Wiring Electrically Isolated CAN Networks

7.2 Heavy Industrial Environment (

Double

 Twisted Pair Cable)

7.2.1 General Rules

NOTICE

esd only grants the compliance with directive 2014/30/EU, if the CAN wiring is carried out 
with single shielded 

double twisted

 pair cables that match the requirements of 

ISO 11898-2.

The following  

general rules

  for the CAN wiring with single shielded  

double

  twisted pair cable

should be followed:

1

A cable type with a wave impedance of about 120 Ω ±10% with an adequate conductor cross-section
(≥ 0.22 mm²) has to be used. The voltage drop over the wire has to be considered.

2

For heavy industrial environment use a four-wire CAN cable. 
Connect  



two twisted wires to the data signals (CAN_H, CAN_L) and 
the other two twisted wires to the reference potential (CAN_GND) and
the cable shield to functional earth (FE) at least at one point.

3

The reference potential CAN_GND has to be connected to the functional earth (FE) at exactly  

one

point. 

4

A CAN bus line must not branch (exception: short cable stubs) and has to be terminated with the
characteristic impedance of the line (generally 120 Ω ±10%) at both ends (between the signals CAN_L
and CAN_H and 

not

 to CAN_GND).

5

Keep cable stubs as short as possible (l < 0.3 m).

6

Select a working combination of bit rate and cable length.

7

Keep away CAN cables from disturbing sources. If this can not be avoided, double shielded cables are
recommended.  

Figure 4:

 CAN wiring for heavy industrial environment

Page 16 of 26

Hardware Manual • Doc. No.: C.2033.23 / Rev. 1.2

CPCI-CAN/400-2

CAN  GND

CAN_L

CAN_H

CAN_GND

n.c.

n.c.

n.c.

n.c.
n.c.

n.c.

n.c.

n.c.

n.c.
n.c.

CAN_L

CAN_H

CAN_GND

Shield

CAN_GND

twisted

twisted

5

6

7

9

8

1

4

3

2

9

1

4

5

6

7

3

8

2

n.c.

n.c.

Single shielded 

double twisted pair cable

(four-wire cable,

2x 2x 0.22mm²)

wire shield

Wire Layout

(Example)

Signal assignment of single shielded double twisted pair cable

 with earth and termination

n.c. = not connected

DSUB9 connector

(female or male)

pin designation

connector case

DSUB9 connector

(female or male)

pin designation

CAN cable with connectors

connector case

earth (FE)

Summary of Contents for C.2033.02

Page 1: ...al PXI Interface Hardware Manual to Product C 2033 02 CPCI CAN 400 2 Hardware Manual Doc No C 2033 23 Rev 1 2 Page 1 of 26 esd electronic system design gmbh Vahrenwalder Str 207 30165 Hannover Germany http www esd eu Phone 49 0 511 3 72 98 0 Fax 49 0 511 3 72 98 68 ...

Page 2: ...ent in any form whole or in part are subject to esd s written approval 2015 esd electronic system design gmbh Hannover esd electronic system design gmbh Vahrenwalder Str 207 30165 Hannover Germany Phone 49 511 372 98 0 Fax 49 511 372 98 68 E Mail info esd eu Internet www esd eu Trademark Notices CANopen and CiA are registered community trademarks of CAN in Automation e V Windows is a registered tr...

Page 3: ... 2011 08 01 1 1 Safety instructions revised 2013 04 19 1 0 Block circuit diagram changed 5 1 Current consumptions corrected P1 P2 renamed to J1 J2 pin numbers corrected 10 Order information revised 1 2 Safety instructions revised 2015 12 10 3 Step 8 Note about CAN termination inserted 5 1 Absolute maximum power and description of additional front panel added 5 5 OnTime RTOS 32 and J1939 protocol l...

Page 4: ...atic discharges may cause damage to electronic components To avoid this please perform the steps described on page 8 before you touch the CPCI CAN 400 2 in order to discharge the static electricity from your body Qualified Personal This documentation is directed exclusively towards personal qualified in control and automation engineering The installation and commissioning of the product may only b...

Page 5: ...16 7 2 2 Device Cabling 17 7 2 3 Termination 17 7 3 Light Industrial Environment Single Twisted Pair Cable 18 7 3 1 General Rules 18 7 3 2 Cabling 19 7 3 3 Termination 19 7 4 Electrical Grounding 20 7 5 Bus Length 20 7 6 Examples for CAN Cables 21 7 6 1 Cable for light industrial Environment Applications Two Wire 21 7 6 2 Cable for heavy industrial Environment Applications Four Wire 21 8 CAN Troub...

Page 6: ...ionally features a PXI interface The signals TRG 0 7 CLK 10 and STAR are controlled via the FPGA The signals LBL LBR1 12 are looped through The PXI interface is available on request Page 6 of 26 Hardware Manual Doc No C 2033 23 Rev 1 2 CPCI CAN 400 2 4 x CAN Core with Timestamp FPGA Xilinx Spartan 3E 32 Bit Microcontroller MicroBlaze Option IRQ A PCI Bridge PLX PCI9056 CompactCI Connector RAM PXI ...

Page 7: ...re 2 PCB top view Attention The jumper JP600A has to be left in delivery status Otherwise the software driver can not be started See also page 14 for signal assignment of the CAN connectors CPCI CAN 400 2 Hardware Manual Doc No C 2033 23 Rev 1 2 Page 7 of 26 ...

Page 8: ...ter etc 2 Discharge your body as described above 3 Disconnect the computer from the mains If the computer does not have a flexible mains cable but is directly connected to mains disconnect the power supply via the safety fuse and make sure that the fuse cannot switch on again unintentionally i e with caution label Danger Never carry out work while power supply voltage is switched on 4 Open the cas...

Page 9: ... 9 Connect the computer to mains again mains connector or safety fuse 10 Switch on the computer and the peripheral devices 11 End of hardware installation CPCI CAN 400 2 Hardware Manual Doc No C 2033 23 Rev 1 2 Page 9 of 26 ...

Page 10: ...rror detected on CAN0 or CAN1 LED500C blinking error occurred on CAN net 0 and or net 1 controller no longer in status BUS OK 1B green CAN 1 Traffic off no CAN bus connection and or no CAN traffic on CAN 1 LED500B blinking connected to CAN bus 1 and CAN traffic on CAN 1 1A green CAN 0 Traffic off no CAN bus connection and or no CAN traffic on CAN 0 LED500A blinking connected to CAN bus 0 and CAN t...

Page 11: ...erface CAN1 CompactPCI board connector X100 110 pin male connector CompactPCI board connector X101 110 pin male connector Only for test and programming purposes X303 X1100 X1101 X1102 reserved for future use Temperature range 0 50 C ambient temperature Humidity max 90 non condensing Dimensions PCB 100 mm x 160 mm Front panel 3U 4HP optional a 6U 4HP front panel is available see order information o...

Page 12: ...dule system potential with pollution degree 1 Bus termination terminating resistor has to be set externally if required Connector 2x DSUB9 male Table 4 Data of the CAN interface 5 4 CompactPCI Bus Host bus PCI Bus according to PCI Local Bus Specification 2 2 PCI data address bus 32 Bit 33 66 MHz Microprocessor optional 32 bit µC in FPGA MicroBlaze Board dimension according to CompactPCI Specificat...

Page 13: ...able The CANopen software package is available for Windows VxWorks Linux QNX and RTX ARINC 825 as another higher layer protocol is available as an option for Windows VxWorks QNX Linux and RTX J1939 protocol libraries are available for Windows others on request 1 For detailed information about the driver availability for your special operating system please contact our sales team CPCI CAN 400 2 Har...

Page 14: ...ignal 1 reserved CANX_GND 6 2 CANX_L CANX_H 7 3 CANX_GND reserved 8 4 reserved reserved 9 5 Shield Signal Description CANX_L CANX_H CAN signal lines of CAN net X X 0 1 CANX_GND reference potential of the local CAN physical layer of CANX X 0 1 Shield shielding connected with the case of the 9 pin DSUB connector reserved reserved for future applications do not connect Page 14 of 26 Hardware Manual D...

Page 15: ...or signal loss across the complete system and cabling parasitic loadings network imbalances ground offsets against earth potential and signal integrity Therefore the practical maximum number of nodes bus length and stub length are typically much lower esd has concentrated her recommendations concerning CAN wiring on the specifications of the ISO 11898 2 Thus this wiring hints forgoes to describe t...

Page 16: ...l earth FE at exactly one point 4 A CAN bus line must not branch exception short cable stubs and has to be terminated with the characteristic impedance of the line generally 120 Ω 10 at both ends between the signals CAN_L and CAN_H and not to CAN_GND 5 Keep cable stubs as short as possible l 0 3 m 6 Select a working combination of bit rate and cable length 7 Keep away CAN cables from disturbing so...

Page 17: ...ted cables is unavoidable take care that the CAN_GND line is not interrupted Figure 5 Example of proper wiring with single shielded double twisted pair cables 7 2 3 Termination A termination resistor has to be connected at both ends of the CAN bus If an integrated CAN termination resistor which is equipped at the CAN interface at the end of the bus is connected this one has to be used for terminat...

Page 18: ... connected to the functional earth FE at exactly one point 4 A CAN net must not branch exception short cable stubs and has to be terminated with the characteristic impedance of the line generally 120 Ω 10 at both ends between the signals CAN_L and CAN_H and not at CAN_GND 5 Keep cable stubs as short as possible l 0 3 m 6 Select a working combination of bit rate and cable length 7 Keep away cables ...

Page 19: ...contacts gender changer are available from esd order no C 1303 01 DSUB termination connectors with male contacts order no C 1302 01 or female contacts order no C 1301 01 and additional functional earth contact are available if CAN termination and grounding of CAN_GND is required CPCI CAN 400 2 Hardware Manual Doc No C 2033 23 Rev 1 2 Page 19 of 26 CAN_L CAN_GND CAN_H FE CAN DP 2 CAN CBX DIO8 CAN C...

Page 20: ...l values of reachable wire length with esd interface lmax m CiA recommendations 07 95 for reachable wire lengths lmin m 1000 800 666 6 500 333 3 250 166 125 100 83 3 66 6 50 33 3 20 12 5 10 37 59 80 130 180 270 420 570 710 850 1000 1400 2000 3600 5400 7300 25 50 100 250 500 650 1000 2500 5000 Table 5 Recommended cable lengths at typical bit rates with esd CAN interfaces Optical couplers are delayi...

Page 21: ...ny www concab de e g BUS PVC C 1x 2x 0 22 mm Order No 93 022 016 UL appr BUS Schleppflex PUR C 1x 2x 0 25 mm Order No 94 025 016 UL appr 7 6 2 Cable for heavy industrial Environment Applications Four Wire Manufacturer Cable Type U I LAPP GmbH Schulze Delitzsch Straße 25 70565 Stuttgart Germany www lappkabel com e g UNITRONIC BUS CAN UL CSA 2x 2x 0 22 UL CSA approved Part No 2170261 UNITRONIC BUS F...

Page 22: ...tance of the CAN data pair conductors and the attached terminating resistors To test it please 1 Turn off all power supplies of the attached CAN nodes 2 Measure the DC resistance between CAN_H and CAN_L at one end of the network see figure above The measured value should be between 50 Ω and 70 Ω If the value is below 50 Ω please make sure that there is no short circuit between CAN_H and CAN_L wiri...

Page 23: ...ata if there is a short circuit between CAN_GND and CAN_L but generally the error rate will increase strongly Make sure that there is no short circuit between CAN_GND and CAN_L 8 4 CAN_H CAN_L Voltage Each node contains a CAN transceiver that outputs differential signals When the network communication is idle the CAN_H and CAN_L voltages are approximately 2 5 V measured to CAN_GND Faulty transceiv...

Page 24: ...k see figure below 2 Measure the DC resistance between CAN_H and CAN_GND see figure below 3 Measure the DC resistance between CAN_L and CAN_GND see figure below The measured resistance has to be about 500 kΩ for each signal If it is much lower the CAN transceiver it is probably faulty Another indication for a faulty transceiver is a very high deviation between the two measured input resistances 20...

Page 25: ...Declaration of Conformity 9 Declaration of Conformity CPCI CAN 400 2 Hardware Manual Doc No C 2033 23 Rev 1 2 Page 25 of 26 ...

Page 26: ...ARINC825 LCD QNX ARINC825 LCD VxWorks ARINC825 LCD RTX C 1101 06 C 1101 17 C 1101 18 C 1101 16 C 1130 10 C 1130 11 C 1140 06 C 1140 17 C 1140 18 C 1140 16 1 For detailed information about the driver availability for your special operating system please contact our sales team Table 6 Order information PDF Manuals For availability of English manuals see table below Please download the manuals as PDF...

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