Control loop for positioning drives in plastics heater units - uses control with exponential characteristic for accurate positioning in min. time

摘要

Control loop is esp. for high-precision positioning drives esp. in HF dielectric heating units for plastics with a variable coupling element between a HF generator and the plastics material. A control element (12) with a specified control characteristic n1 at which a disturbance variable (15) occurs is connected in series with an actual value unit (16) with linear proportional behaviour to produce the control variable (X) which is fed to a subtraction circuit (2). The latter receives a command variable (W) to form the control deviation. The subtraction circuit output is connected to the input of a linear amplifier (3) with the pre-set gain (V1) whose output is connected to the dividend input of a divider (8). The command variable is fed to a distortion circuit (17) with expontial transmission characteristic whose output (18) is connected to the divider's divisor input. The divider output (9) is fed with the control deviation to a transmission element (10) whose output (11) feeds the final control variable.