Setting up Compax3 C3I12T11128 192-120113 N08 C3I12T11 - December 20104.1.8. Defining jerk / rampsIn this chapter you can read about:Jerk limitation .................................................................................................................128Ramp upon error / deenergize .......................................................................................1294.1.8.1 Jerk limitationDescription of jerkJerkThe jerk (marked with “4” in the drawing below) describes the change inacceleration (derivation of the acceleration)The maximum change in acceleration is limited via the jerk limitation.A motion process generally starts from a standstill, accelerates constantly at thespecified acceleration to then move at the selected speed to the target position.The drive is brought to a stop before the target position with the delay that hasbeen set in such a manner as to come to a complete stop at the target position. Toreach the set acceleration and deceleration, the drive must change the acceleration(from 0 to the set value or from the set value to 0).This change in speed is limited by the maximum jerk.According to VDI2143 the jerk is defined (other than here) as the jump inacceleration (infinite value of the jerk function).This means that positionings with Compax3 are without jerk according to VDI2143,as the value of the jerk function is limited.Motion sequencet4ttt1231: Position2: Speed3: Acceleration4: JerkHigh changes in acceleration (high jerks) often have negative effects on themechanical systems involved. There is a danger that mechanical resonance pointswill be excited or that impacts will be caused by existing mechanical slack points.You can reduce these problems to a minimum by specifying the maximum jerk.Without jerkaccording toVDI2143
