DE1089046B - Electrical control device with hysteresis characteristics - Google Patents

Description

The invention relates to an electrical control device with hysteresis characteristics, in which for each Direction of rotation of the servomotor or the like. A relay is provided which is polarized by the contacts of a relay Relays with zero position are brought to the pickup and in which the polarized relay with a Contact pressure amplification is provided in such a way that the regulation takes place on the setpoint. Such Control devices are known, but they require a relatively large effort, z. B. Moving coil relay with multiple windings. The object of the invention is to provide a to create simple control device which z. B. a servomotor for the lens aperture of a television camera depending on the brightness of the recorded scene in such a way that the image pickup tube always works in the most favorable range of characteristics. The required controlled variable, e.g. B. a control voltage, can be generated with the help of a photocell aimed at the scene, its light intensity is varied by a device coupled to the lens diaphragm. However, it is also possible to do this Obtain control voltage from the video signal. The regulation should be done in such a way that with a constant change in brightness readjustment of the diaphragm is carried out in leaps and bounds in such a way that as possible few control processes are required.

To achieve the objects described, the invention consists in that the polarized relay supplied Control voltage counteracts a fixed bias voltage, which is taken from a voltage divider is and is lowered by the circuits of the actuator switching relay so that A compensating current in the same direction is superimposed on the fault current flowing through the polarized relay. An embodiment of the invention is characterized in that the polarized relay in the Display diagonal of a bridge circuit, the branches of which are next to the measuring element, ζ. B. photocell that Contain windings of the relay switching the servomotor.

An exemplary embodiment is given below with reference to the figures the invention explained.

Fig. 1 shows a circuit diagram of a control device according to the invention. Depending on the polarity of the control voltage U '%, which is supplied by a photocell H , for example, the polarized relay P pulls in one of the two switching relays A and B , which for example set a servomotor M in the desired direction of rotation. The resistors i? ₄ and i? ₅ determine the rest potential, where the absolute size of these resistances i? ₄ and R _{5 is} expediently chosen for reasons of symmetry so that the internal resistance of the electrical control device
with hysteresis characteristics

Applicant:

Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Witteisbacherplatz 2

Dipl.-Ing. Hans Breunig, Karlsruhe-Hagsfeld,
has been named as the inventor

is equal to the internal resistance R _{1 of} the control voltage source.

If the control voltage deviates from the rest potential, the contact / * is moved to the left or right, so that a current flows through relay A or B and R ₁ , which increases the potential at relay A and resistor R ₂ or relay B and resistor R ₃ lowers. If the polarity of relay P is correct, the excitation of this relay is increased, since an additional current now flows through the relay effect via R ₂ or R _3. When the control voltage drops as a result of the control process that begins, the corresponding contact of relay P will finally open and the potential at A or B will increase again. This restores the original state, and with the appropriate dimensioning of the resistors, the rest potential is reached.

The capacitances C ₁ and C _{2 in} parallel with the resistors R ₂ and R ₃ result in an improvement in the stability due to a differential component of the returned current when switching.

In Fig. 2, the operation of the arrangement according to the invention is shown as a diagram. Here, I _p means the current flowing through the winding of the polarized relay P , the pick-up currents being denoted by Ia ₁ and Ia _2. The control voltage plotted along the horizontal axis is labeled Ur. Point B is the nominal value of the control voltage, while points and C represent the starting points of the control process.

Claims (2)

PATENT CLAIMS: 1. Electrical control device with hysteresis characteristics, in which the Servomotor or the like a relay is provided, 009 607/287 which are brought into attraction by the contacts of a polarized relay with zero position and in which the polarized relay is provided with a contact pressure reinforcement such that the Control to the setpoint takes place, characterized in that the polarized relay supplied Control voltage counteracts a fixed bias voltage, which is taken from a voltage divider is and lowered by the circuits of the relay switching the actuator that will be the one via the polarized relay. residual current flowing equal to a compensating current Direction superimposed. 2. Control device according to claim 1, characterized in that the polarized relay in the Display diagonal of a bridge circuit is whose branches next to the measuring element, z. B. photocell, contain the windings of the relay switching the servomotor. Considered publications:
German interpretative document No. 1 001 377. 1 sheet of drawings ® 009 607/287 9.60