DE2515080A1 - ACTUATOR FOR OPERATING AN ACTUATOR - Google Patents

Description

Patent attorneys

Dr. E. Bottttner
Dipl.-Ing. H.-J. Müller

Dr. Th. Berendt

D 8 Munich 80

Lweit-Grabu-äU. 38, Tel. 47 Sl 55

(LANDlS & GYR) LANDIS & GYR AG CH-63O1 Zug, Switzerland

Actuator for operating an actuator

The invention relates to an actuator in the preamble of the claim mentioned Art.

As is well known, an actuator has the task of an actuator - for example a valve, a cock or a valve Air damper - to be actuated as a function of a control signal, which is usually in the form of a control voltage. There are electromotive, electromagnetic and electrothermal Actuators known. Electromotive actuators working according to the servo principle essentially exist from a subtracter, an electronic or electromechanical one Three-point switch, a servomotor and a feedback potentiometer coupled to the servomotor. The subtracter forms the difference between the control voltage and the voltage tapped at the feedback potentiometer. This differential voltage arrives at the three-point switch, which depending on the size and sign of the difference is three possible Can assume switching states and accordingly the servomotor in the forward direction, in the reverse direction or to a standstill switches. As a result, the servomotor assumes a position (manipulated variable y) that of the position applied to the servomotor

Control voltage. /

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An actuator of the type described above is also known, to whose control input not a control voltage, but rather a variable resistor can be connected via a two-wire line. This enables a position transmitter to be connected directly to the actuator, which means that the actuator can be remotely controlled manually or automatically without an external voltage source.

The invention is based on the object of creating a simple actuator that has both a control voltage as well as can be controlled with a variable resistor. The solution to this problem is achieved through the in the license plate of the claim designated features. The advantages of the actuator according to the invention are in its universal Applicability, in the thereby achieved simplification of storage as well as in the created possibility see, at the same time with a control voltage and with a position transmitter designed as a variable resistor affect the actuator.

An exemplary embodiment is given below with reference to the single drawing figure the invention explained in more detail.

In the drawing, 1 denotes an actuator, the housing of which is indicated by a dash-dotted line 2. A supply terminal 3 for connecting an alternating voltage leads to a supply circuit 4 which outputs a direct voltage U. and a direct voltage U ″. A control terminal 5 is connected via a resistor 6 and a control terminal 7 via a resistor 8 to a summing input 9 of a subtracter 1O. The resistors 6 and 8 together with the amplifier (not shown) of the subtracter 1O form an adder 11. A resistor 12 is connected on the one hand to the control terminal 5 and on the other hand to the DC voltage source U ₁ . The output of the subtracter 10 is connected to a three-point switch 13 which controls a servomotor 14. This servomotor supplies a manipulated variable y

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for actuating an actuator, not shown. To the Servomotor is also coupled to a feedback potentiometer 15, between the supply voltage source U and a reference potential terminal 16 is switched. A voltage divider consisting of a setting resistor 17 and a fixed resistor 18, whose tapping at a follow-up input 19 of the subtracter 1O is connected, is with the wiper of the feedback potentiometer 15 and connected to the reference potential terminal 16. The wiper of the feedback potentiometer 15 is also connected to an output terminal 2O of the actuator 1 .

The subtracter 1O can be part of the three-point switch 13 if this has a differential amplifier on the input side. The adder 11 can consist of the two resistors 6, 8 and a separate amplifier connected as a computing amplifier. A separate amplifier for the adder can, however, be omitted if the amplifier of the subtracter 10 or v /. of the three-point switch 13 its function takes over. The servomotor 14 can be fed with direct current or with alternating current and accordingly directly to the Outputs of the three-point switch 13 or via two relays, triac or the like controlled by the three-point switch. Can be connected to an alternating voltage.

The control terminal 5 and the reference potential terminal 16 can a position transmitter 21 designed as a variable resistor can be connected. If no such position transmitter is used control terminal 5 must have low resistance to the reference potential terminal 16 can be connected. A control voltage source 22 which has a control voltage U. delivers, is sent to the Control terminal 7 and the reference potential terminal 16 connected.

To explain the operation of the actuator described, it is assumed that U ₁ = 2 LL and that the resistance values of the resistor 12 and the feedback potentiometer 15 and the maximum resistance value of the position transmitter 21

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are the same size. It is also assumed that the resistors 6, 8, 17 and 18 are high-resistance compared to these resistors and that the resistors 6 and 8 on the one hand and the resistors 17 and 18 on the other hand are of the same size. A control voltage U_ drops across position transmitter 21, which - depending on its resistance - can assume a value between zero and U ". The voltage U tapped at the wiper of the feedback potentiometer 15 can vary to the same extent. _{A voltage 1/2 (U 1} + U_) is applied to the summing input 9 of the subtracter 1O and a voltage 1/2 U is applied to the follow-up input 19. If these voltages are not equally large, the three-point switch 13 switches the servomotor 14 on with the correct sign until U _y = U ₃₁ + U ₅₂ .

The actuator described opens up universal application possibilities. It can be used without position transmitter 21 in a control device to operate any actuator. The output voltage of the regulator serves as the control voltage U here . . With a variable resistor as position transmitter 21, the actuator can be used, for example, for remote adjustment of air flaps.

Finally, both control options can be combined with one another, e.g. by changing the output voltage of a controller and also a position transmitter 21 can be connected to the actuator, with the position transmitter being a minimum limit or manual remote control. The position transmitter 21 can also be controlled by a second controller be formed, the output side has a variable by the controller resistor, the resistance value of the Represents the manipulated variable of the second controller. A particularly advantageous option is to use a position transmitter Use a frost protection sensor, which is activated when the temperature, e.g. in a heating register, falls below a specified value causes the actuator operated by the actuator to open continuously.

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To output terminal 2O and reference potential terminal 16 One or more two-point switches 23 can be connected, which provide a control signal to control other organs output when the voltage U or the manipulated variable y proportional to this voltage exceeds predetermined threshold values. or fall below. By connecting a position indicator 24 to terminals 16, 20, the actual value the manipulated variable y can be made visible in a simple way. Finally, the terminals can be used for so-called follow-up control 16, 2O with the terminals 16 ', 7' of one or more others Actuators 1 'are connected, so that the position of the servomotor 14 on the servomotors of the other actuators is transmitted.

With the setting resistor 17, the feedback of the output voltage U to the follow-up input 19 of the subtracter 10 and thus the dependence of the output voltage U or the manipulated variable y from the control voltages U - and U can be changed. This allows the characteristic to be adapted of the actuator to the possibly distorted characteristic of the actuator and / or other organs - e.g. a heat exchanger - the regulated system.

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Claims (7)

PAT EN CLAIMS Μ.) Actuator for operating an actuator, in particular for valves and air flaps in heating, ventilation and air conditioning systems, with a subtracter and a three-point switch to control a servomotor depending on a control voltage, and with a coupled to the servomotor, feedback potentiometer acting back on the subtracter, characterized in that the subtractor (1O) an adder (11) is connected upstream, at one adder input (?) A control voltage (LJ -) and at its another adding input (5) connected to a voltage source (LL) via a resistor (12) as a variable Resistance trained position transmitter (21) can be connected. 2. Actuator according to claim 1, characterized in that a wiper of the return potentiometer (15) to a Output terminal (2O) of the actuator (1) is connected. 3. Actuator according to claim 2, characterized in that a two-point switch (23), a position indicator (24) or a control terminal (7 ¹ ) of a further actuator (I ¹ ) can be connected to the wiper of the feedback potentiometer (15). 1846 809838/0559 4. Actuator according to claim 1 or one of claims 2 and 3, characterized in that the position transmitter (21) is a frost protection sensor. 5. Actuator according to claim 1 or one of claims 2 and 3, characterized in that the adder (11) consists of two connected to an input (9) of the subtracter (1O) Resistors (6; 8) consists. 6. Actuator according to claim 5, characterized in that the subtracter is formed by a differential amplifier on the input side of the three-point switch (13), at its summing input (9) the adder (11) and at its follow-up input (19) the tap of a with the wiper of the
Feedback potentiometer (15) connected to the voltage divider (17, 18). 7. Actuator according to claim 6, characterized in that
that the voltage divider (17, 18) consists of a setting resistor (17) and a fixed resistor (18). ^PA1846 609848/0559 Le e rs e ite