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. LabChart should recognize the PowerLab and the new Front-End Amplifiers/Signal Conditioners input connection scheme upon opening.
For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE.