A plasma probe assembly for use in a plasma processing chamber is provided. The sensing device further comprises circuit means for summing the pixel output signals of subsets of pixels including at least two pixels and for generating, for each of the subsets of pixels, a summed output signal, the processing means determining the measurement of relative motion based on the summed output signals. One preferred embodiment of a hose fitting for filling tank cars with particulate matter comprises a t-shaped pipe that defines a bore there-through.