How can I set up the RTH for correct CAN decoding?

Question

I want to decode a CAN bus signal with my RTH. Which settings must be done to perform a measurement?

Answer

The following options must be available to perform CAN bus analysis on the RTH:

R&S®RTH-K3 CAN/LIN triggering & decoding (1333.0550.02)
and / or R&S®RTH-K9 CAN FD triggering & decoding (1326.3829.02) for the faster CAN FD bus.

The RTH user manual gives information about both options in chapter 9.5 (Version 1326.1578.02 ─ 15) beginning on page 205. It also describes the CAN bus protocol in general. We will explain the measurement on the Low Wire in this example. Please perform the following steps on your RTH to measure the Low Wire information of a CAN signal:

Connect Ch1 to the CAN signal source
Be sure to be in the Scope Mode ([MODE]-"Scope")
Press <PRESET>
Press <AUTO SET>
Change the time Base to 2ms/div
all the following steps will need to scroll the available menu up or down to find the wanted menu point.
Open the "Bus" Menu by touching the R&S logo on the right lower screen and then choose "Bus"
Change the Protocol type to "CAN" and set the State to "I"

Change the Protocol type to "CAN".

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Change the Protocol type to "CAN".

Now open the Config-Menu (under the protocol selection) and take care to have the right settings (can be different to the screenshot)

Config-Menu

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Config-Menu

Leave the menu now. If all settings are fine, you should see the desired information. Otherwise try to use the "Find Level" function in the menu before.