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Hello, My model is a solenoid valve ，and the armature displacement range of 0-0.5mm. I use the Newton's second law to describe it :d(v,t)M-Fz+kp-4[N]=0, in it, d(v,t) is the acceleration, M is the mass, Fz is the electromagnetic force，k is the Spring stiffness, p is the displacement，4[N] is the pretightening force of Spring. In order to limit the displace in 0-0.5mm，I used "Event" to stop，but my result have a problem, as shown in attachment. During the time t1, because the electromagnetic force is less than 4[N]，the displacement is minus. When the current is 0, the electromagnetic force changes to 0, and the armature acts as a return motion under the action of spring force. But during the time t2 , the displacement is also minus. So I want to ask how to add conditions to limit the displacement , making it change 0 during t1 and t2 ??? Look forward to your reply， thank you.