Just like the write process, use the Configure TDMS Channel for Read. Using this we can do more efficient reads, finding only the frames that have a desired CAN ID. Using my API there will also be a second channel in the TDMS file recording the CAN IDs of the frames logged. The result will be a TDMS file will has CAN frames data flattened, and written to the channel specified. Then call the Write CAN frames to log to the TDMS file. For writing first use the Configure TDMS channel for write, providing all the information you can. After installing the Hooovahh CAN File IO package, you'll have a subpalette devoted to reading and writing to a TDMS file. That's why I've cleaned up their code, and added a few features like logging CAN IDs as a separate channel for filtering purposes. Like many examples done by NI they only go so far, and are usually not the most efficient. The basic example can be found in the CAN Input Stream to TDMS Logfile.vi example, which gets installed with the XNet drivers. Luckily NI provides some examples on how to go from CAN frames to a TDMS file and it just requires one channel within one group. When a TDMS file uses this standard format for CAN data, some of NI's tools like DIAdem can read the TDMS file and recognize it has CAN data in it. So how can CAN data be stored into a TDMS file? Well luckily NI came up with a standard that flattens raw CAN frames into an array of bytes, and can then read the data back turning it into frames. TDMS also has all kinds of interesting features like properties. You have a file (like a workbook) with multiple groups (like a worksheet) with channels (columns in a table) and samples in those channels (rows in a table). It is best understood as a file format that is similar to Excel. The TDMS file itself is a very interesting topic, and one that I've presented on in the past at NI Week. This code and examples can be installed by installing the Hooovahh CAN File IO package, which will be referenced in this post, and is available on the downloads page for this blog series. In this series we will talk about reading and writing CAN data as TDMS files and BLF files, as well as talk about other common operations like reading HEX, and S record files, which will be important for later blog posts.

Since CAN data is generally a complicated data structure consisting of multiple data types, saving it to a file isn't always easy, and you may come up with something that works, but is non-standard and requires non-standard tools. But we haven't yet talked about formats of saving CAN data to a file.

Throughout this series we've talked about how to read and write signals and data and so forth.

Ni tdms to excel