MS3-Pro + Microsquirt + AIM MXL logging dash CAN Bus

[prof315]

I'm doing some research for a probable upcoming project that is going to have an MS3-Pro (engine), Microsquirt (trans control) and AIM MXL Strada logging dash all tied together on the CAN bus and I have a question..... Reading through the info on CAN I know that only 2 of the units should have a terminator resistor. The AIM MXL Strada is going to be used solely to display info from the MS3 Pro, will this still apply? And if so what would be the best way to connect and set up the CAN bus? I have used AIM stuff before and it has been super easy to set up ( enable CAN, connect the AIM unit to the MS, and select the desired data to collect on the AIM unit using the AIM Race Studio software.... DONE) I'm just wondering if adding the Microsquirt is going to make things more difficult since it will be sharing data with the MS3-Pro and vice versa.

Thanks

Jeff

[racingmini_mtl]

The terminating resistors have nothing to do with what the devices are doing or what data is sent/used. That's an electrical requirement. The MS3 and Microsqurt have no way to remove/disable the terminating resistor so if your AIM unit has this possibility, you will need to remove/disable the terminating resistor.

And if everything is set correctly, you should be able to have all three device working together by simply connecting them to the CAN bus. As for the settings, I don't know the trans controller nor the AIM unit so someone else will have to chime in.

Jean

[prof315]

So if I cannot remove the terminating resistor in the AIM (assuming there is one in there somewhere), I'm going to have issues?

Jeff

[racingmini_mtl]

That won't be according to specs. I have run many tests like that on the bench and never saw anything wrong but I may have missed whatever happened as there is some low-level CAN protocol stuff happening that is pretty much transparent to the user. But there's also the fact that the bench is not a very harsh environment so it might be more problematic in the car.

Ideally, you'd want to remove the resistor on one of the device. It would not be that difficult to do on the Microsquirt for someone used to working with surface mount components. I have no idea what it looks like on the MS2Pro or the AIM. But I'd give it a try as-is before trying to removing surface mount components (or even through hole components).

Jean

[racingmini_mtl]

From a quick search, it seems that the AIM MXL has a non-removable terminating resistor. That seems like a bad idea for such a CAN device. That's why I do provide some sort of jumper or DIP switch in all my CAN devices.

So you will probably want to try it first as-is. And if you have any issue you may want to try removing R18 from the Microsquirt.

Jean

[prof315]

I spoke with the tech support guys at AIM and they are going to remove the terminating resistor before shipping it to me. ( I have a friend/customer who is an AIM dealer and has a direct line to the US tech support team at AIM) They said it _might_ work with the resistor in place but that it was far more likely for one of the units on the CAN network to simply not communicate. Anyhow it looks like the problem is solved. Thanks for your input Jean.

Jeff

[prof315]

Well AIM didn't remove the resistor from the logging dash so I went ahead and pulled R18 off of the Microsquirt...... And it works! I have CAN communication between the MS3-Pro and Microsquirt even without the AIM dash hooked up. Thanks once again Jean!

Jeff