Racegrade TC8 + Omega Thermocouples

[hamer]

Thanks to both of you.

I've scoped the 12V, ground and haven't seen anything that's out of the ordinary. I have not checked the CAN bus yet, but I'll try that. Should I be looking for voltage on it?

It's strange because we are running the C125 with the bike's CAN, and another CAN logger, with no issues or drop outs. For some reason CAN2 has issues.

Is there any other setup I need to do with the TC8? I just added it as an E888 per the instructions, but do I need to change any of the settings under the CAN bus in the communications window? Or load a DBC file for it to properly see the thermocouple inputs?

[adrian]

What do the temperature channels actually do? Are they dropping out completely or do they just look noisy and have unexpected values?

This is most likely caused by noise from the HV cables between the inverter and the motor, how do you have the cable shielding connected?

[hamer]

I tried to post a video but for some reason it wasn't posting. Basically every time I rev the motor the values jump around. Mostly drop. I think Dave might be right, CAN is cutting out and they are going to default value (0C). I might try to change the default to something more obvious and try again.

I didn't have this issue with any other sensors, including the analog temp sensors I was using. The only reason I switched to thermocouples is because I needed a 3rd input and figured it would be best to use all 3 of the same sensor.

[hamer]

Video

[Stephen Dean]

That looks like the CAN is dropping out and the values are dropping to the default values set. The test would be to set the default to well above the range that the data will be in at the moment and see what happens. You can also add a Comms CAN Diag x channel into the Expander Diagnostics receive template and log that diag channel at 100hz to see what the diag is doing. I'd say that it will be swapping between 0 and 512 (No Data) with maybe some 4096 (Bus Warning) and 8192 (Bus Off) as well.

[hamer]

That looks like the CAN is dropping out and the values are dropping to the default values set. The test would be to set the default to well above the range that the data will be in at the moment and see what happens. You can also add a Comms CAN Diag x channel into the Expander Diagnostics receive template and log that diag channel at 100hz to see what the diag is doing. I'd say that it will be swapping between 0 and 512 (No Data) with maybe some 4096 (Bus Warning) and 8192 (Bus Off) as well.

Thanks Stephen, I'll try that in the morning.

If it does happen to be the CAN dropping out, what's my path forward to fix it? The wiring appears to be fine. Using twisted pair to CAN2 bus, it's the only device on the bus and I'm using a termination resistor. Should I try re-programing the TC8 to the correct baud rate to work on CAN1? Since I know that bus is working? Are there any other settings I can adjust in the software to help?

[Stephen Dean]

See what Diag code gets spat out when you apply the diag channel to the receive template, there are a couple of other values that can also come up that are related to the use of the expanders, and depending on the error reported, there may need to be some other changes to be made.

[hamer]

I haven't got to logging the CAN errors yet, but I'm starting to lean against that theory. I set the default values to 800C and when it flutters it doesn't go anywhere near there.

[hamer]

Anything besides these channels I should log?

CANcomms.JPG (76.52 KiB) Viewed 7904 times

[Stephen Dean]

The Diag Channel is normally loaded here.

Diag logging.jpg (34.96 KiB) Viewed 7901 times

These have been enabled?

CAN Bus Channels.jpg (56.65 KiB) Viewed 7901 times

If so, just add them into the logging, they do not need to be part of a template.