is there a way to modify the CANoe Rx Messages before Receiving on the Bus? - can-bus

Question

I'm Receiving CAN Message from my Controller(Suppose Message ID= 0x100 signals S1,S2),
But I want to change the signals of Canoe Rx message before Receiving it on the Bus.

Answer 1

basically if you want to change something in a CAN frame you can do something like this in capl.
Example:
Framename: TEMP
Signal you want to change: S1, S2
on message TEMP /* or "on message 0x100" in your case */
{
/* if you have a dbc or arxml assigned to the canoe project you can directly
* use frame names and signal names to manipulate the data.
* if not you need to use it's ID and write over the bytes on it.
*/
this.S1 = whatever_value;
this.S2 = whatever_value;
output(this);
}
If you don't have a DBC/ARXML file added to the project, but i highly recommend to do so. The only thing you need to change in the above code that you have to specify which bytes you overwrite.
You change this:
this.S1 = whatever_value;
this.S2 = whatever_value;
To this:
this.byte(0) = whatever_value;
this.byte(1) = whatever_value;
But you need to know which bytes you need to overwrite.

Answer 2

If you cannot modify the message before being sent by the Controller, your only option to modify your message is a HIL (Hardware In the Loop), which you position between the sender (Controller) and CANoe VNs on the bus.
They are called CANStress modules for instance, if you wish to stick to Vector products.
They will sniff the messages on your bus, and at the defined trigger (by you) will overwrite the Physical Layer with whatever you wish, successfully altering or fault-injecting the bus.
Be aware, that modifying the signals means you have to know their mapping, also how to recalculate the CRC tag and modify that also, otherwise the CANoe VN will not accept your message, and will report Rx_Err CRC Check.