CANBUS Paameter Mapping

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BLF0005
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CANBUS Paameter Mapping

Post by BLF0005 »

Hello everyone,
I am struggling to get the CAN mapping correct for all of the Tx messages I am trying to send from the inverter to my Controller.

My main issue at this point is the motor speed. It is currently mapped through the web interface to ID: 178 Position: 0 Bits: 16 Gain: 32 and this results in the inverter sending a value of 0018 in the first two bytes of the frame which is 6144 in decimal all the while the inverter is reporting 0rpm within the web interface. I have also tried a gain of 1 with no success. What am I missing here?
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johu
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Re: CANBUS Paameter Mapping

Post by johu »

Seems like you did everything right. Are you aware that everything is decimal including ID?
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collin80
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Re: CANBUS Paameter Mapping

Post by collin80 »

johu wrote: Thu Oct 28, 2021 7:40 pm Seems like you did everything right. Are you aware that everything is decimal including ID?
From what I can tell, a lot of people are confused by that. I mean, other than DBC files I have never seen anyone specify CAN ids as decimal. It just feels sick and wrong. Is there any way that IDs on the parameter mapping form could be specified in hexadecimal? I think it'd be a lot more natural for basically everyone. As it stands quite often one has to translate the IDs people give them into decimal because everyone specifies the IDs in hex. Also, why isn't there an option to apply offset to the values? There are quite a lot of things that really should be transmitted with offset - temperatures in particular. Almost everything ends temperatures as degrees celsius + 40 so that you have to apply a -40 offset when you get the temperature. Nobody likes sending negative numbers or explaining what 2's compliment is.
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johu
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Re: CANBUS Paameter Mapping

Post by johu »

Yes good points. I could add translation to the web interface for now, e.g. when a value if prefixed with "0x" or so.
There is actually a branch of the CAN module with offsets. The only issue is backward compatibility. If I introduce it now old CAN maps won't load. Shame on me for not having a version by in front of the structure.
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