garygid
Member
BlackKnight said:... any active node has no choice. ACK is part of the message acceptance algorithm. If you receive a frame and accept it then you will set ACK. Listen only mode just disconnects the TX line so that your ACK goes nowhere. Thus, your choices are to be in listen only mode and only receive traffic or be in normal mode and be able to send when you want to and always ACK anything you receive.
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working with ...
- Model S, Think City, Nissan Leaf, custom cars. Not a one of them ever had a problem with my attaching a listener device that wasn't in listen only mode. A lot of other people have used the same tools on various cars.
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never heard of any issues that can be traced to being in normal mode. Allowing a device to send ACK is only really a problem either if you have the wrong bus speed set or if the bus is in very bad shape. So, I find myself agreeing that listen only mode is the proper way to go for absolute safety.
But, I also find the proposed danger to really not exist. In practice I have never once had a single issue with just leaving my tools in normal mode and going about my business.
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In practice you won't go wrong if you use tools in listen only mode when you are doing straight captures. Sometimes you need to do a capture while also poking a stick into the beehive to see what happens. Then you can't be in listen only mode but, from my experience, nothing bad will happen due to being in normal mode. Just sharing my experience which seems to be different from some other people's experience. This could come down to hardware. I use the EVTV hardware and Kvaser hardware, not cheap $5 boards or anything like that. If you are using a kazoo and a can of silly string to monitor your canbus then perhaps you should use listen only mode for safety.
We also had no problems with the LEAF when we accidently used the Regular Receive mode (with ACK).
Perhaps our one-time problem with the Model S was with something other than the ACK.
When I am able to Log again, I will first get it working with listen mode, since my AVR-CAN
boards now have the TX solder jumper removed. Then I will try the same hardware and
software in the proper Receive Mode (with the TX solder jumper replaced).
Thanks for sharing your very helpful experience with us.
Cheers, Gary