BUG in canopen library??

[miguelRT]

Hello everyone,

I am using 

Hardware: CAN PCI-2 High speed

Software: NI CAN 2.3          and CANOPEN library 1.0

I am programming a master CANOpen node connected to 8 slaves and sometimes it seems to work but sometimes it doesnt. Sniffing the CAN bus with another computer I find that everytime I try to send an CANOpen object, what the card really sends its the object repeated several times, sometimes twice sometimes more than 20 times.

I have tried with a minimal vi sending NMT objects, which I attache, and it always send the object twice instead of only once.

Is this a bug??, or there is some solution to avoid this situation.

[Javier_Gutierrez]

Hi MiguelRT

    The CAN standard requires any recievers of a message to send an acknoledgement that the message arrived. It might be the object in your network that takes a little bit too long to send the acknoledgmenet so the board sends the message twice.

Hope this helps
Javier Gutiérrez
NI Application Engineering

[miguelRT]

Thank you Javier,

I will do some tests having your answer in mind. Just in case do you know have some more information about the time before retransmission?

how long is it?

Is it configurable?

Is it hardware dependant or software?

Is it part of some standard or a manufacturer free decision?

Thank you

Miguel Núñez

[Javier_Gutierrez]

Hi Miguel

  I don't know for sure the answers to your questios, but if you look into the CAN Board user manual, you'll see that transmision rates are system dependant (basically cable lenght) so my guess is that time depends also on it.

Hope it helps

Javier Gutiérrez
NI Application Engineering