| 摘要 |
A control system for a pneumatic valve actuator comprising three operating blocks memorizing respectively the values of the spring pressure pm, the counter-thrust pressure pc and the friction pressure pa for the various valving member position values, said blocks being connected in parallel and, via a switch, to the valving member position transducer or to the set position generator and connected to the pressure computing block connected via a second switch to the pressure generator or, together with the value read by a transducer for the pressure existing in the actuator, to a differentiator connected to two multiplier units for K and for (1-K) respectively, which are connected to the transit memory of the pc operating block and to the pa operating block respectively, the switches being driven by a logic control unit which switches over when the valving member is at rest. Means are provided for sensing anomalies and the extent of wear.
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