I have 3 devices in a CAN bus system.
1st device is isolated from the others by using the PCAN optoadapter.
CAN BUS data rate is 250kB/sec
1st sends 4 TPDOS at 100ms.
2nd device sends 1 TPDO at 10ms
3rd device sends 4 TPDOs at 100ms.
Cable length 2-3meters. The 1st device distorts the bus as the following figure shows: When I reduce the 1st device TPDOS to 2, then there is no issue on the bus.
Unfortunately I do not have access before the isolation but only after were all devices are connected.
Do you have any hint why this is happening?
Please check the termination on your system in an unpowered state, make sure
you have around 60 Ohms between CAN-High and CAN-Low on both sides.
It could be possible that you need additional termination on your primary side.
Please report back to us with your findings.
Eventually I was able to replicate the fault that the customer sees in the lab.
The issue is time related because the power supply of the PCAN opto-adapter goes lower than the PCAN opto-adapter threshold and this makes it to complain.
When I reduce the TPDOs then the needed power is lower and the issue goes away.
I will upload some more photos tomorrow.
Please make sure the PCAN-Optoadaptor is properly supplied with the needed voltage throughout your tests.
Furthermore, did you manage to obtain the aforementioned pictures?