The computer may have issues recognizing the Front-End Amplifiers/Signal Conditioners if you try to change channel inputs while a LabChart file is open. The correct way to change inputs is to do the following:
1) Save any necessary data and close LabChart.2) Turn off the PowerLab using the off/on switch on the back.3) Switch your amplifiers/Signal Conditioners to the desired PowerLab inputs.4) Turn the PowerLab back on.5) Open a new instance of LabChart, a settings file, or the file previously saved. Upon opening, LabChart should recognize the PowerLab and the new Front-End Amplifiers/Signal Conditioners input connection scheme.