This is a known issue in LabChart for Windows (versions 7.2 and later), and occurs when using the Legacy/Computed Input feature. Legacy/Computed Input is the historic method used to perform channel calculations on raw data. This feature is still included in LabChart to provide backwards compatibility for files recorded with archived versions of the Chart/LabChart software.
To fix files that are experiencing this scaling issue, the following steps will need to be performed:
- With a PowerLab connected to the computer and turned on, open the file experiencing this issue with LabChart for Windows.
- As pictured below, open the Setup Menu, and select the "Channel Settings..." option.
The Channel Settings window will now appear. As demonstrated in the following image, turn off the inputs that are performing the Legacy/Computed Input calculations.
- Re-accomplish the calculations in the appropriate channels with a LabChart channel calculation.
- Finally, save the file to with the new calculation settings.
Note: If using Chart 5 or newer, ADInstruments strongly recommends using Cyclic Measurements
or another current Channel Calculation option, which will prevent this issue as well as provide a more flexible and powerful calculation method.