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CAN bus operation

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(@doctor-542)
Posts: 17
Member Customer
Topic starter
 

Hi!

I'm using 2 VFD's for fans with Modbus RTU communication.
Modbus RTU to CAN converter, bidirectional, ( https://www.waveshare.com/wiki/RS232/485/422_TO_CAN) purchased as well.
Seems I could see some parameters of the VFD's - speed, power, current.

Is it possible to control VFD's via YourDyno software - e.g. automatic Fan Speed vs Motor RPM control, On/OFF via hotkeys?


 
Posted : 19/08/2025 3:14 pm
(@cmadmin)
Posts: 102
Member Admin
 

You can send out any data channel on the CAN bus. There is a little trick if you want to send a hotkey over the CAN bus. Install the KmTronic plugin (even if you don't have the KmTronic, it does not matter). Define a channel there and assign a hotkey. The channel can now be sent out via CAN


 
Posted : 24/08/2025 1:05 pm
(@doctor-542)
Posts: 17
Member Customer
Topic starter
 

I guess the plugin is needed.

Direct CAN data of speed (or rpm) is not enough for the VFD's. To control Fan RPM we have to send RPM target - formula based calculated value...
Also to turn ON/OFF the fan the different commands to be used, e.g for start 0002h and 0005h for stop (modbus).


 
Posted : 26/08/2025 8:14 am
(@cmadmin)
Posts: 102
Member Admin
 

The CAN out is made such that it sends the channel values out continuously. If a channel is start/stop (02h/05h) then it will send 02h as long as the channel value is 02h and then 05h as long as the channel value is 05h. You can have another channel which is speed which comes from a math channel where you calculate the desired speed based on whatever other channels shall define this, then send this channel out on the speed CAN id. 

 


 
Posted : 26/08/2025 8:31 am
(@doctor-542)
Posts: 17
Member Customer
Topic starter
 

Posted by: @cmadmin

The CAN out is made such that it sends the channel values out continuously. If a channel is start/stop (02h/05h) then it will send 02h as long as the channel value is 02h and then 05h as long as the channel value is 05h. You can have another channel which is speed which comes from a math channel where you calculate the desired speed based on whatever other channels shall define this, then send this channel out on the speed CAN id. 

 

Good idea, thank you! I'll try and let know.

 


 
Posted : 26/08/2025 8:33 am
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