Do I need terminating resistor in my CAN setup ?

I have Two PC based CAN Applications installed in my computer, CANoe and a proprietary application.  
CANoe application needs to talk over 11-bit CAN to embedded target board via Vector VN1630 CANCase.  
Proprietary application needs to talk over 11-bit CAN to embedded target board via a dongle.

Target Board, CANCase, and dongle need to have same CAN connection.  The purpose of CANCase is to only monitor message exchanges between dongle and target board.  CANCase won't transmit any messages.

Do I need a terminating resistor in my setup ?   If yes, exactly where should it be inserted ?  What should be the value, 120K Ohms ?
LVL 1
naseeamAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

naseeamAuthor Commented:
My baud rate is 125000
0
naseeamAuthor Commented:
Bus length is about 2 feet.  

It's a low speed CAN Network.
0
d-glitchCommented:
A diagram is worth 1000 words.
Do the devices at the ends of the bus have optional terminations?
0
Ultimate Tool Kit for Technology Solution Provider

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy now.

naseeamAuthor Commented:
>>  Do the devices at the ends of the bus have optional terminations?

I didn't understand the question.
0
d-glitchCommented:
The best advice from     www.ti.com/lit/an/slla270/slla270.pdf
     The Standard defines a single line of twisted-pair cable with the network topology as shown in Figure 6.
     It is terminated at both ends with 120-Ω resistors, which match the characteristic impedance of the line
     to prevent signal reflections.

Good advice from     http://www.keil.com/forum/21024/can-bus-one-60-ohm-instead-of-two-120-ohm-resistors/
     You can accomplish the termination (on a small network) with a single 60 ohm ...

Maybe adequate advice from the second source
     For short cables, you can often get by without any termination.

You definitely have a short cable.  At 125 kHz, one wavelength would be 2400 meters.

In order of ease.
    Do nothing and see it works.
    Put a 60 ohm resistor anywhere in the network.
    Put two 120 ohm resistors at the endpoints of the network.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
d-glitchCommented:
>>  Do the devices at the ends of the bus have optional terminations?

Many times a device will have a jumper to connect a terminating resistor when the device is at one of the endpoints.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Automotive

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.