Connect a 15T or 26T teaching series PowerLab to your computer and turn it on. Open the experiment in the LabAuthor program, and take a look at the Stimulator Settings in LabTutor Kernel View.
If the Isolated Stimulator box is not checked, please check it, and click the On button to the right of the checkbox.
Save your changes, generate a new experiment installer file, and upload the updated experiment version to the LabTutor Server. The stimulate button should now be active in the experiment. If you need further assistance, please contact ADInstruments Technical Support.