We are developing a system using the CAN bus to implement the network connecting different nodes. We have a PC that needs to ask for some data (the node status) to the nodes that have to answer to the request immediately. In order to ask each node for its status we send a "remote frame" message to the CAN bus with a specific ID. The relevant node has to answer with the relevant data by using a "data frame" message. Each node is in a while loop reading a buffer and sending back data when necessary. Usually everything goes well but sometimes it happens that one of the nodes does not answer to the PC request, even if the request is sent to the bus (it is seen by another node and it can be seen by using an oscilloscope connected to the CAN bus lines). It seems the node do not see the message, it misses the interrupt for updating the buffer... We usually send a sequence of "remote frame" messages waiting every time for the answer: send ,waiting for answer, send, waiting, ... Even if we insert a sleep between a send and another, sometimes the messages are missed by a node... We modified the baud rate (from 500Kbit to 20Kbit) but the problem is not solved. We are using a T89C51CC03 micro-controller by ATMEL.
Have you ever experienced this problem? Any suggestion?
Thank you in advance for any help!