The Force Plate, order code FP-BTA, $245 will measure compression and tension forces, normal to the flat top surface of the plate. The plate is designed to measure larger compression forces than tension. Tension force measurement will require that the plate be attached to other things, such as handles on both the top and the bottom.
The Force Plate does not measure any forces parallel to the surface.
The Force Plate, like all force sensors, has a finite response time that limits the use of the plate to impulses longer than the natural period of vibration. This means that the Force Plate cannot respond to impulses lasting less than about 4ms, since the natural frequency is about 250 Hz. Striking the force plate with a hard object, or throwing a baseball at it, will result in impulses shorter than the natural period. In this case the data show the response of the Force Plate, not the actual impulse.
It is fine to stand or jump on the force plate. Maximum non-damaging force is 4500 N (1000 lb) compression or 900 N (200 lb) tension evenly distributed. Note that a hard 50 lb object can exert considerably more than 1000 lb peak force if dropped from a distance.