CAN breakout box

[brosian]

Hello,

does somebody know, if this CAN Breakout Box can be powered also by connecting the supply voltage directly to V+ and V- (not just via Power Connector)?

I cannot find any documentation from this box, just that it should provide 12V on V+ when powered from 8-30V on the power connector. So can i connect directly 12V to V+ and nothing will happen with the box?

Many thanks for the info!

[Hooovahh]

I don't have one anymore, but when I did have one of these I was pretty sure all it did was wire all the DB9's together, and break them out.  So to me what that should mean is powering it through the terminal or through the barrel plug should be the same.  Do you have a DMM to check with?  Put power on V+ and V- and it should provide that on the DB9s.

Also if you are using the terminating resistor function, it doesn't require power it just puts a resistor between pins 2 and 7.  There isn't really any function this box does that requires power.

[ulaci · Accepted solution]

Although it is possible to power the bus directly from the V+ and V- pins (these are all connected internally across the connectors as Hooovahh pointed out), it was not designed to be used in this way. The main concern here is the lack of protection, that takes place between the power connector and the V+ and V- pins (so the power coming from the plug goes through this protection circuit before reaching the V+ and V- pins). It is a circuit that limits the current and prevents back-driving to the PS, so in case of powering directly from V+ and V-, it is the users responsibility to ensure this kind of protection.