Troubleshooting CAN4VSCP

Troubleshooting CAN4VSCP

When things does not work, we have to search for the reason for why it does not work. As always, this means to be patient and systematic. Here we list some info on troubleshooting a CAN4VSCP bus.

Power

Power or no power?

Power is the first thing to check when everything is wrong. If the power lamp (RED LED) on the module lights up, the power is probably OK. If not, you definitely have a power problem. If you have your bus connected with a CAT-5 or similar network cable, you should have 9-28V on the orange/orange-white/green-white cables and 0V on the brown/brown/white/green cables. You have the complete pinout here.

Just besides the RJ-45 connector on most CAN4VSCP modules, you can find a pin list where the bus power and ground is available. They are on the outer pins on this pin list. Check the schema for your unit.

Connection problems

The node starts up and just blinks

Very common problem. CAN/CAN4VSCP requires that there are two active nodes on the bus at the same time. If not, CAN/CAN4VSCP will not work. If you have equipment so you can look at the bus traffic in such a situation, you will see a lot of traffic. This is the same event sent over and over again because it is never acknowledged. Remember that a Frankfurt RS-232 or other CAN adapter is a valid active device only when it is active/open.

Node does not react on read register etc. but sends events out on the bus

This node probably have some problem with its reception channel. Most often a cable problem, sometimes a transceiver problem on the board.