Get Variable from mdfObJ based on ChannelGroupNumber

I know that there is this example of a command in the vehicle network toolbox documentation.

[data,time] = read(mdfObj,chanGroupIndex,chanName,startPosition,endPosition,"OutputFormat", "vector")

[data, time] = read(m, 1, "Triangle", 1, 10, "OutputFormat", "vector")

For my case this does not work, because the extraction of the data needs to be automated and the entire channel should be extracted.

For instance in a mdf-object there is the variable d2s. Its Channelgroupnumber is for instance 2.

Then I can easily access it. so far so good..

But in my case mf4-files with different sizes are loaded into matlab with the mdf-command.

So far i was not able to figur out how to search thru the data for the channelgroupnumber of a specified channelname that i want to output as a vector.

I know that with the channelList(m) (m=mdf('xxx.mf4')) command I get a table with information about Channelgroupnumber, channelname,...

But I don't get to the point to implement it into the read-command.

Hope you guys can help!

Answer 1

[Tushar]

Hi Dennis,

It is my understanding that you want to read the data from an MDF-file for a specific channel. Currently, you are using the ‘read’ function for this purpose. It is important to note that the ‘read’ function is no longer recommended and might be removed in a future release, as mentioned in the documentation you referred to, the link to which is mentioned below.

https://www.mathworks.com/help/vnt/ug/asam.mdf.read.html

It is recommended to use the ‘mdfRead’ function to directly access the MDF-file. To read all data from the MDF-file for specified channel names, you may use the below command.

data = mdfRead("VehicleData.mf4", Channel= ["*Torque" "*Rate"]);
% Here, we are reading the data for the ‘Torque’ and ‘Rate’ channels

For more information on the ‘mdfRead’ function, see the below documentation.

https://www.mathworks.com/help/vnt/ug/mdfread.html#mw_7b8f643e-4a37-4125-bd24-c97ed18e1c0b

To transition your ‘mdf’ object code, you can find additional information in the below documentation.

https://www.mathworks.com/help/vnt/ug/transition-your-mdf-object-code.html

I hope this helps resolve the issue you are facing.

Regards,

Tushar