Racegrade TC8 + Omega Thermocouples

MoTeC supplied sensors, valves or wiring discussion

Re: Racegrade TC8 + Omega Thermocouples

Postby Stephen Dean on Thu Jun 29, 2023 12:00 pm

Are you unplugging from the Vehicle CAN Bus when connecting the PCAN device? It may be between the TC8 and Dash that the CAN Bus is picking up the noise.
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Re: Racegrade TC8 + Omega Thermocouples

Postby hamer on Thu Jun 29, 2023 12:06 pm

Here’s another video showing the behavior.

Video
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Re: Racegrade TC8 + Omega Thermocouples

Postby hamer on Thu Jun 29, 2023 12:07 pm

Stephen Dean wrote:Are you unplugging from the Vehicle CAN Bus when connecting the PCAN device? It may be between the TC8 and Dash that the CAN Bus is picking up the noise.


Yes unplugged from Vehicle CAN. But when connected to the MoTeC it’s a very short run, again the TC8 is the only device on CAN2, and it’s not reporting any errors.
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Re: Racegrade TC8 + Omega Thermocouples

Postby David Ferguson on Thu Jun 29, 2023 12:17 pm

The PCAN devcie may be optically isolated (I think mine is), and might be able to handle larger differential voltage offsets. Again, my experience was an induced 30v offset onto the CAN bus that caused the problem - shielding the CAN bus helped, but fixing the short in the motor case, solved it completely.
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Re: Racegrade TC8 + Omega Thermocouples

Postby hamer on Sat Jul 01, 2023 5:16 am

David Ferguson wrote:The PCAN devcie may be optically isolated (I think mine is), and might be able to handle larger differential voltage offsets. Again, my experience was an induced 30v offset onto the CAN bus that caused the problem - shielding the CAN bus helped, but fixing the short in the motor case, solved it completely.


Switching to shielded CAN lines, should I leave the shield floating? Or should I ground one end of it? To chassis ground?
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Re: Racegrade TC8 + Omega Thermocouples

Postby Stephen Dean on Mon Jul 03, 2023 9:45 am

To the 0V on the Dash.
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Re: Racegrade TC8 + Omega Thermocouples

Postby adrian on Tue Jul 04, 2023 9:49 am

I would be pretty carefully about just connecting the CAN shield to the Dash without really analysing your shield/grounding topology for the whole bike. If you don't have shielded HV cables it's pretty easy to induce noise into all sorts of other systems.
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