| 摘要 |
By the use of actuators, e.g., for servo controlled adjustment of movable parts of hospital beds, it is desirable to make use of a remote indication of the actuator positions or of adjustment to predetermined positions. The position of an actuator is suitably detectable by measurement on an associated potentiometer (4). In accordance with the invention it is also desirable to use only three connector wires between the actuator and an associated control box (6), and when two of these wires have to carry the motor current it is problematic to measure the position of the potentiometer through another pair of wires, because the motor current is variable. According to the invention, the problem is solved in deriving from a point of a voltage divider in the motor circuit an expression of the potentiometer position in combination with an expression of the motor current, while deriving from an outer section of the voltage divider an expression of the motor current alone, whereby it is possible, by means of a calculating unit, to create an expression of the potentiometer position independent of the motor current. |
