FAQs from Rohde & Schwarz

How can i setup the RTH for correct SENT decoding?

Question

I want to decode a SENT bus signal with my RTH, but i only get the information about the fast channel. Which settings must be done to also get information about the slow channel?

Answer

To decode SENT bus signals, the RTH must be equipped with the RTH-K10 option. A description of the SENT protocoll and the of the SENT option (RTH-K10) can be found in chapter 9.7 of the manual (Rev. 1326.1578.02 ─ 1) beginning at page 216.

The data of both, the fast and the slow channels is transmitted simultaneously, by including two bits of a slow channel message in the message frame of the fast channel.

Either the frame lenght of the fast channel or Pause / Pulse must be set to be able to encode the slow channel.

Please perform the following steps on your RTH to measure the slow channel information of a SENT signal:

- Connect Ch1 to the sent signal source

- Press <PRESET>

- Press <AUTO SET>

- Change the time Base to 50ms/div

- all the following steps could 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 "SENT" and set the State to "I"

How can i setup the RTH for correct SENT decoding?

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

How can i setup the RTH for correct SENT decoding?

It is very important to set the Message Format to Enhanced or Short and to input the correct Frame lenght or set „Pause / Pulse“ - otherwise the slow channel won't be decoded or displayed.

- Leave the menu now. If all settings are fine, you should now see the slow channel information:

How can i setup the RTH for correct SENT decoding?

It is also possible to display the content in list format:

- Press <MODE> and choose Protocol

- The display now changes to the list mode

How can i setup the RTH for correct SENT decoding?

- Open the Scope Menu again by touching the R&S logo.

- Touch Protocol and set the table view to "Slow Channel"

- The display now should change and show the slow channel information.

When you have loaded an adequate label list, you can also show this label information to make it easier to identify messages.