Automotive and Embedded Networks
Loading .ldf files through Vector XL Driver - LabVIEW wrappers
Where does it say that loading an LDF is part of TroyK's wrapper VIs or the XLWrapper DLL at all? Loading an LDF is possible and parsing it through NI's XNet which can function on a software layer and not require XNet hardware.
An LDF file has a couple purposes. The first and easiest to understand it it can be used similarly to a DBC is on CAN, in that it defines what bits of a payload are used for what signals, and scaling. This LDF will say things like "If my ID is 0x123, then the first byte is Temperature and it is from X degrees to Y degrees". If you open an LDF in the XNet Database Editor (check your start menu after installing XNet) you should be able to see how the scaling is done. This is most convenient for times when you want to read or write values as engineering units. It is easier to read RPM then it is to read 8 bytes and have to figure out the scaling to get RPM. I cover the DBC and the Signal API in this part of my CAN blog. That is CAN specific but XNet shares lots of concepts between CAN and LIN.
Another thing the LDF has which a DBC doesn't, is information about the schedule used. LIN is different than CAN in a few ways and one of them is that data being transmitted is done by a master and slave setup. So if you are the master you will be responsible for the schedule to be used. The master populates the header for these schedules, and the slave(s) respond with the payload data. This is somewhat like a request response system where the master can optionally reply to its own request. This means that the LIN bus is effectively always at 100% bus load. It isn't quite since there are delays between requests but once the schedule has been serviced it starts back over again. The more data to request, the longer it will be to go through the schedule and get all data again.
So what I suspect you can do, is use the XNet API to read the LDF and get scaling information, and schedule information. Then using Troy's API you can be the master or slave and request or respond to data based on the schedule in the LDF. Using XNet LIN hardware would make this easier, but I realize that might not be an option. I've personally never used LIN Vector hardware in LabVIEW.
Troy's library has a couple LIN examples, one being a slave, and the other with some kind of simulation interface with the master requesting data that the slave responds to. I'd start with these.
