A company manufacturing brake controllers for towing trailers needed an in-vehicle test system that monitored various quantities (i.e. brake temperature, vehicle speed, brake distance, etc). The company needed the system to be flexible enough to add or remove data channels as needed. They also needed a triggering function (i.e. when a data channel reached a certain level the data acquisition would begin). Logging the data to an excel file was required. A read back function was needed to display the data for analysis purposes.
We used National Instruments Fieldpoint hardware to interface between the transducers and the laptop computer that was located in the vehicle. This hardware was an inexpensive solution allowing us to add additional channels with minimal cost. We developed a program using LabVIEW to setup the necessary data channels, collect the data, and read the data back for analysis.
The Setup screen consisted of a table containing the required setup information. We added a function that allowed the user to save different setup configurations and load those into the setup table. The set up screen allowed the user to enter the channel name, the channel number that corresponded to the Fieldpoint hardware, the Fieldpoint module used, the user defined scale the data was to be associated with, the gain and offset, line color, and trigger voltage. During data acquisition, if the channel input voltage was above the trigger voltage, the program would erase all the data prior to the trigger voltage, and continue to collect data for a user specified length of time.
The Data Acquisition screen acquired data from the fieldpoint hardware and displayed selected data in the graph. All the data collected was saved to an excel file for analysis.
The Readback screen displayed the saved data from an excel file. The user had the ability to turn plots on/off, turn scales on/off, perform minimum, maximum, and average values for all plots shown, zoom in on plots, and print the graph to any printer on the network.
The system met the customer’s requirements with minimal cost. It was also easy enough to use so training time was minimal.
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