Racegrade TC8 + Omega Thermocouples

[hamer]

I'm attaching a logfile that shows the drop outs, not seeing any CAN errors though. Channels to look at are: Cooler Outlet Temperature, Controller Outlet Temperature, Motor Outlet Temperature.

I'm not seeing any errors reported on the channels you asked me to log.

One thing I noticed, when I connect to the TC8 via the PCAN device that the instructions recommended, the temp values are rock solid and don't move with any throttle revs, but as soon as it's plugged back into the C125 it has the flutter. Seems like there is something with how the MoTeC is receiving the values or displaying them? I tried to run the C125 just off CAN2 with only the TC8 plugged in but it still didn't work. Is there anything with CAN2 and RS232 that could be causing issues? I am using the GPS.

Also attaching my C125 config.

Thanks all for the help at this point.

[Stephen Dean]

Has the TC8 been reprogrammed to transmit at 500k? By default they are set to 1M.

[hamer]

Yes, I reprogrammed it to 500k to match CAN1 just in case there was some interference or it had anything to do with it.

[Stephen Dean]

Can you reprogram it to 1M and set the configuration to 1M as well, I'm wondering if there is too much data coming across at 500K for it.

[hamer]

I will do that in the morning, but that’s how it was originally set with all the issues, I only changed to 500k on my last attempt of the day to fix it.

[hamer]

Just wanted to give an update. Tried a bunch of different things today, switching CANBUS to 1, baud rates, etc.

Only one thing worked that mostly stabilized the readings, changing the 12V input. I was using the MoTeC race kit harness ECU connector which uses the same BAT+/- as the C125. When I powered the TC8 via a different 12V source on the vehicle there was a huge improvement in the stablity of the readings. It still isn't perfect under heavy throttle, but much better. I'm going to run with this for now, but will need to keep digging to figure out why.

Any ideas welcome.

[adrian]

Like I said before this is most likely caused by noise from the HV cables. How do you have the shield on the HV cables grounded? Are you using shielded cable for the CAN wiring?

[hamer]

Like I said before this is most likely caused by noise from the HV cables. How do you have the shield on the HV cables grounded? Are you using shielded cable for the CAN wiring?

We don't use shielding on the HV lines, never caused any type of issues in the past. Will need to look into that.

[adrian]

That'll be it then, most likely the thermocouple amp is picking up noise and giving you incorrect readings.

[hamer]

That'll be it then, most likely the thermocouple amp is picking up noise and giving you incorrect readings.

I just don’t understand how it would pickup noise when attached to the vehicle CAN, but not when direct to PC via the PCAN device. In both cases it’s powered by the vehicle, and the same throttle inputs are applied.