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Reference Number: AA-01569 // Views: 0 // Created: 2018-12-13 19:36:32 // Last Updated: 2018-12-13 20:12:15
Problem & Solution
LabVIEW Panels: Connecting Multiple Signals to a Waveform Graph


When connecting multiple RT-LAB signals to a waveform graph in my LabVIEW panel, I receive the following error:

Unable to create connection: Two sources of data can't be connected to a same input.

How can I connect multiple signals to a LabVIEW Waveform Graph?


This error can occur if the LabVIEW Waveform Graph is configured in Single Plot mode rather than Multiplot mode.  Please follow the steps below to ensure that your VI is properly configured.

Step 1: Open the panel VI in LabVIEW by right-clicking the panel name in the RT-LAB Project Explorer and clicking Edit

Step 2Navigate to Help >> Show Context Help in LabVIEW to open the Context Help window

Step 3Hover over the graph you'd like to connect to and make sure it is a LabVIEW Waveform Graph.  Waveform Charts, XY Graphs, and all other components in the Graph palette are not supported in RT-LAB LabVIEW Panel

Step 4Make sure the Waveform Graph input is configured in Multiplot (two-dimensional) mode by following the steps described below

    • In the VI Block Diagram, right-click the wire input of the Waveform Graph terminal block and click Create >> Constant
    • Verify that the array constant is two-dimensional, as shown on the left side of the image below.  If necessary, right-click the array constant and select Add Dimension
    • Delete the array constant if desired
    • Save and close the VI

Step 5In the RT-LAB Project Explorer, hold down the Ctrl key to select multiple dynamic signals

Step 6Drag and drop the selected signals onto the Waveform Graph in the LabVIEW panel