UniCan Send Unican problem

[Guest Jan N.]

Hi all!

I have a problem with two V230 controllers. I intended to use CanBus to put two V230 controllers to communicate with each other. On V230 is intended to send to another V230 some data and opposite. They both have similar programms, but the problem is that one way the communication works but opposite way it doesn't. The distance between the two controllers is only about 30 - 40 cm. Shorlty, I structured a vector from MI-s, Mb-s and ML-s (32 byte) and then I sent the vectror to another controller if the data changed in that vector. It seems, that both controllers are sending and doesn't indicate any communication problems, but one "receives" the data and another doesn't. May that problem be in cable, because there was so little needed that cable (and my local distributor sayd that if I would like to buy the exact cable, I have to buy 50 m, because they doesn't sell less), that I used some kind of 4 wire sheilded cable which is not twisted. Then I put resistors to both end. I think that if the communication works on one way it should work on oposite direction also? Or am I wrong?

Any Ideas?

[Simon]

I doubt the cable is a problem over such a short distance (though some may disagree). I have had CAN working over several different "non ideal" cables, though usually just for testing. However I would always recommend using the specified cable type for a permanent installation.

Also, if the communications is working in one direction, that would indicate that the cable is transmitting the data OK.

Check things like your unit IDs and CAN status bits and integers.

What is triggering the send that fails to be received? If you are trying to send too fast there will be problems. If it is event-driven, check whether you have a vibrating/bouncing contact or fluctuating analogue signal that is triggering a send more frequently than you expected.

[Ofir]

Hi Jan,

As Simon already mentioned, Check the IDs of the PLCs and check also in UniCAN send the destination ID and the destination start of Vector.