As stated above, a microeinstein per square-meter per second is equal to a micromole of photons per square-meter per second. PPF (Photosynthetic Photon Flux) is the integration of μmol photons m-2 s-1 between 400-700 nm. So, if your μE measurement is also photons between 400-700 nm, then it will be equal to PPF. If that is not the case, you're going to have some trouble converting.