DE1062814B - Circuit arrangement for the automatic adjustment of a measuring circuit - Google Patents

Description

GERMAN

The invention relates to a circuit arrangement for the automatic adjustment of a measuring circuit using a preferably decadic adjustable by means of several step switches Normal, in which each step switch is assigned a stepping mechanism that moves forward or backward, the about suitable, depending on one means of their size and polarity the amount and the direction of the Incorrect adjustment indicating the DC control voltage actuated switching elements to a common pulse generator is switchable, and in the switching elements in the connecting lines of the stepping mechanisms to Pulse generator are arranged.

With such circuits it is possible to adjust the setting of a z. B. in a bridge or compensation circuit existing adjustable comparison standard to make automatically in such a way that a Adjustment is achieved without the person measuring his working hours and manpower for meaningful activity the operating elements of the reference standard needs to spend. Such automation During the adjustment process, the person measuring can work, for example, on several measuring arrangements at the same time or simultaneously evaluate the measurement results during the measurement on a measurement arrangement.

In this context, adjustable standards can include both gradually changeable Resistances, capacitances or inductances should be understood as well as others in comparison measurements adjustable balancing agents used, such as B. attenuators or similar auxiliary measuring devices.

The previously known circuit arrangements for the automatic setting of standards in measuring circuits however, mainly have the disadvantages that they either in their mode of action or in their Structure are extremely complicated. So is z. B. a bridge circuit is known in which the automatically adjustable Standards can be controlled in such a way that all setting values are run through in sequence until the adjustment is achieved. Such an adjustment method can, however, be used for certain sizes of the adjustment value lead to relatively long adjustment times.

In another known bridge circuit, the step-wise adjustable normal is switched on a stepping mechanism is used, which is operated by the diagonal branch current. However, it is here a further switching of several step switches each regulating one decade of the adjustable standard in a meaningful chronological sequence with the aim of a particularly short and wear-saving one Overall setting not possible.

Furthermore, a bridge circuit is known which enables automatic display of the difference between the ohmic resistance values of two bridge branches-a circuit arrangement for automatic operation
Adjustment of a measuring circuit

Applicant:

Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Wittelsbacherplatz 2

Ewald Braun, Munich,
has been named as the inventor

light. This is achieved by placing a larger number of auxiliary branches on the feeder diagonal are, each of which consists of a series circuit of three resistors, of which the middle one means a switching device can be assigned to either one or the other bridge half. The individual auxiliary branches are scanned one after the other via a selector, with the middle one Resistance is switched on in such a way that the sign of the diagonal branch voltage is not is changed. This results in a gradual approach to the optimal bridge equilibrium Corresponding allocation of the mean resistances in the auxiliary branches. During this adjustment process first the coarse adjustment with the help of larger mean resistances and then with the appropriate assignment The fine adjustment is carried out with ever smaller mean resistances. However, a fine adjustment to be able to carry out a control range spanning several decades are this known circuit requires significantly more measuring resistors than is required for an arrangement would be the case with several decadic step switches. Also the one for scanning the auxiliary branches necessary relay circuit is very expensive, so that the entire measuring circuit has a significant circuitry Requires effort.

Another known circuit arrangement for setting a decadic standard works in such a way that, beginning with the fine-regulating decade, so many decade switches are timed run through one after the other to the end stop until the adjustment value to be set is less than one Is below the control unit of a decade. Then the smaller decades are shown one after the other in

909 580/174

3 4

the way that the other digits of the Ab- actuated the step switch, with which the adjustment at the equivalent value is only brought about after the complete fastest, and on the other hand, those decade switches are reached which, depending on the current setting, regulate this more finely than the decade to be set in each case. In the case of a step switch, however, a movement in the direction of such a complicated setting process is effected. After completion of the setting, on the one hand the setting time is large and on the other hand the development of this tap changer is then the fine wear and tear of the fixed and movable mechanical regulating tap changers in the same rational manner and electrical components, in particular the contact,
beats, relatively strong. In the following a preferred embodiment

For the same purpose, a circuit arrangement of the invention is already shown in more detail with reference to the figures has been proposed that purifies the adjustment.

an adjustable standard mastered in a very short time, Fig. 1 shows an appropriate control switch

without doing this through the individual step switches, while in the

necessary long contact paths must be covered, Fig. 2 and 3 signaling circuits shown

so that the response time of the conventional arrange- 15 _s i _n d, through which the shortened gene mismatch or the adjustment and closure of the mechanical of the measuring circuit can be displayed.
Components is reduced. In this circuit, as can be seen from FIG. 1, the adjustable

This arrangement is achieved by actuating the step normal of three preferably decade step switches forward and backward stepping devices I, II, III, which are assigned to the step-by-step, the direction-dependent switching 20 rotation of their actuating axes each presenting means depending on the polarity of a means of _{un (resetting} step switch mechanism Iv j ₁ Uv, IHV polarity and magnitude, the direction and the amount of, or Ir, Hr have ₁ her. These are optional indicating to mismatch control voltage either a common pulse generator G connectable coupled to a pulse generator are connectible, and that in _the further circuit of the stepping mechanisms appropriate interconnectors from the step derailleurs ₂₅ pulses emits. the individual stages of switches to the pulse generator further switching members in such a way j _n direction from I to III, respectively wirvorgesehen finely regulating, that until the setting of a step - k _{eIlj s} ; _nc j is appropriately numbered according to the adjustable switch to the norm value above the adjustment value, for example when setting the next higher level its introducing, then for one of the switched-on resistance with χ 100Ω, χ- 10Ω, its resetting pulse and then the forward _{30 x} .] _ q _{0 (s} j when setting the transmission loss alternate end stepper of the next finer regulating, with λ "1 neper, .ζ ·· 0.1 Neper and λ - 0.01 nepers, if in the idle state to zero provided the tap _{changer, a} decadic assignment Stufenschalzum the individual pulse generators are connected through. ter each other is provided. Here, each χ

In such a circuit arrangement must by which the position of the respective tap changer are still satisfies the condition that the one given ₃₅ JE.

individual step switches at the beginning of the adjustment in the Tj _he adjustment of the measuring circuit, which are located by a zero position. For this purpose, a separate correct setting of the step switches I, II, III her control circuit is provided, to which the feedback can be added, is controlled by a DC voltage occurring at all the step switches in their zero position, terminals 1-1. However, the reset time is lost by the tat ₄₀ whose polarity and magnitude, the direction and the Besächlichen adjustment time, indicating particularly at _tra g of the current mismatch.
Row settings is disadvantageous. In addition, the DC control _{voltage is evaluated at Tjj e}

Series settings The adjustment time for the next size and polarity is unnecessarily extended by the following control setting if the polarized relays K, L, M with mean values of both settings differ only slightly from _{each other} . In this case must namely _who have te. The response current of the individual tap changers initially corresponds to the _{value of} the relay K, preferably approximately that control zero position and then again partly to the same current that is brought to position as before when the tap changer I is adjusted. Would thereby advertising _e ine level from the calibration position to occur, the at screening the tap changer more ₅₀ Furthermore, the relay L and M claimed necessary with such Anals and wear of the speaking current values provided that unnecessarily large for them relative mechanical components. the same applies to step switches II and III.

The invention is based on the object of providing a decadic, unknown circuit arrangement, assuming that the stages of the circuit arrangement mentioned for the self-switch I, II and III against each other decadic calibration of a measuring circuit are the disadvantages of the _{55 stages} to avoid. graduation of the response current values of K, L and M.

According to the invention, this is achieved by flowing in the control containing the terminals 1-1

that the switching means belonging to the switching devices circle a control direct current of such a size, direction-dependent and from the control direct voltage that the polarized relay K are influenced with the greatest influence and a number of graduated 60 speaking current values are excited, so are in dependent response thresholds and that the switching - Ability of the polarity of the direct control current through organs are arranged in such a way that, depending on the closing of the contacts kl or k2, the control relay A is energized by the greatest response or B exceeded in each case. The control relay A then switches over a certain step associated with it, its contact al the introducing stepping switch with the stepping device selected depending on the polarity 65 / w of the step switch I to the pulse generator G , while B over & 2 the resetting Is stepped through. Werk Ir turns on. The assignment of the control relays

The circuit arrangement according to the invention has A, B to the polarized relay K has the essential advantage that it is automatically switched on to the pulse generator G when that stepping mechanism of the step switch start of a new balancing process is on the one hand only 70 ters I, the

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allows the tap changer to move in the direction of the adjustment position. When the step switch I is moved, the adjustment is thus improved from step to step and the DC control voltage or DC control current occurring at terminals 1-1 is correspondingly reduced. When the control relays A ₁ B are energized, the contacts al, bl, α3, & 3 prevent the control relays C, D, E, F from responding, which control the other polarized relays L, M

all head contacts go back to their rest position by one switching step. After that then is the state achieved that the next coarser regulating tap changer was moved by one level and the S considered tap changer is in the position before the end position and from here in the direction of the now achievable adjustment position is moved. Step into the illustrated embodiment when the tap changer II moves into the upper one

that step switch is set which brings the adjustable standard into the adjustment position the fastest brings, and only then successively more finely regulating step switches are operated.

When the step switch I arrives at the step closest to the adjustment value, the drop-off current value of the relay K is undershot by the control direct current, so that the closed idle

are assigned with lower response current values. io end position of the head contacts Hol, IIο2 and IIο3 This measure is necessary so that initially only in activities that cause a shutdown of the stepping mechanism Hv, a connection of Iv and a connection of Ilr to the pulse generator G. After a transmitted pulse, these three stepping mechanisms assume the positions described, which serve as the starting position for a new setting movement of the tap changer II. The other contacts II u 2, II u 3 are correspondingly assigned to the head contact II u 1. Corresponding contacts contacts al, bl the control relays C ₁ D of the step switch 20 III o2, IIIö3 and IIIm2, IIIm3 also work with the ters II depending on the position of the contacts 11, 12 of the pole head contacts III 0 1, IIIμ 1 of the step switch III ized relay L are energized. This is about the together.

Contacts el, dl an actuation of the control relay E ₁ F The further contacts shown in the figure

or the tap changer III initially prevented. Only Iu2 and Io2 are used to prevent resetting after setting the tap changer II to the level closest to the position of the tap changer II from its end position by the adjustment value is in the corresponding end position. The armature goes into the rest position (/ 1 and 12 open) head contact II w4 is used for the same purpose when Er-C and D are switched off and via the closing reaching lower end position of the step switch III, rest contacts el, dl the control relays E, F des in stages ₃₀ f _a n _ss i _cn the tap changer already II also actuated in the switch III. lower end position.

There is thus a setting for the individual In order not to receive any control oscillations, it is

Step switch takes place in such a way that at first it is necessary, with decadic steps, to operate the one whose associated polarized switch is energized, with the exception of the coarsest regulating relay, and of all simultaneously energized ₃₅ to 11 step. Otherwise polarized relays would have the highest response current value of a tap changer on the lower head contact. But this only after completion of setting this s _wa when set to the value "0" of the case, the tap changer is the anchor of the polarized relay, the nächstgröber regulating tap changer sinnin back to the rest position, thus setting the staged according to one level be reduced, switch is silent and lifts the block for the next _{40 has} the consequence that the first-mentioned tap changer in more finely regulating tap changer. its position "10" must run in order to achieve the same

The connection of the step switches II and III to achieve control value. In this position, the pulse generator G takes place in the same way as in the case of the step switch via the corresponding head contacts the next switch I through the contacts c2, d2 or el, f 1 of the coarser regulating step switch again by one step corresponding control relay C ₁ D or E ₁ F. Increase from the +5, so that a control oscillation would arise in each case the step switch released for setting, at which the step indicating the value "0" is actuated the step switch that moves the step switch between its end positions and the next switch from the one at the beginning of its Adjustment process with more coarse regulation would oscillate between two levels, the present position in the direction of the adjustment. The selection of the step switch mechanism ₅ o the step switch are in position "10", and depending on the polarity, the next coarser regulating step switch is reduced by one step for the DC control voltage at terminals 1-1.

met that at the beginning of the adjustment movement according to another preferred embodiment

Step switch is present. the circuit arrangement according to the invention can

Head contacts are arranged on each step switch, depending on the direction, several in terms of size, which switch off the step-by-step switches when they come up to response thresholds by means of an end position from the pulse generator G and form a single polarized step relay, thus stopping the step switch. In the case of the step, the individual contact steps of the contacts k I ₁ k 2; switch I are z. B. in the upper end position the l \ _} 12 and ml, m2 correspond to the figure. In this case, however, in step-by-step switching mechanism Iu via the head contact 1 01 and 60, in order to avoid the resetting step-by-step switching mechanism Ir via ImI, a number of step switches must be actuated at the same time. With the remaining tap changers, additional contacts are assigned to each excitation level, and further head contacts are assigned to them, which, when running, break the excitation circuits of the control relay belonging to the lower tap changer in an end position of a connected excitation level, subdividing the stepping switch acting in the same direction.

According to a further preferred embodiment, the step switch acting in the opposite direction to the circuit arrangement according to the invention can also operate the step switch associated with the step switches I, II, III by a further control relay A, B ₁ C ₁ D ₁ E ₁ F is optionally switched on by clock, so that after a reset 70 are excited that their excitation circuits of photo

Claims (6)

diodes are influenced, which are arranged for the optical evaluation of the DC control voltage according to size and polarity. For this purpose, a direction-sensitive display instrument is preferably used, the pointer position of which is scanned with the aid of the photodiodes arranged distributed on the scale. A selection is made among the step switches according to the size of the pointer deflection and a selection is made between the two stepping mechanisms of the selected step switch depending on the side of the scale according to which the pointer is deflected from the middle zero position. In detail, for. B. the pointer be illuminated and with its shadow affect the corresponding photodiode its display position so that the current flowing through it is reduced, an auxiliary relay located in this circuit drops out and brings the control relay corresponding to the pointer position to respond via its break contacts. According to a further development of the invention, a display device can be actuated if the necessary adjustment value cannot be achieved by a step switch. An appropriate signaling circuit for the step switches I and II can be seen from FIG. In the excitation circuits for the control relays A, B belonging to the polarized relay K, a common auxiliary relay H is provided, which closes a signaling circuit for the display device Ll (e.g. indicator lamp) via a contact h 1 if one of the two switches to the first step switch associated head contacts Iu4 or Io4 is closed and thus the tap changer I is in one of its end positions without the associated polarized relay K having dropped out. A corresponding display for the step switch II can take place by means of the auxiliary relay / and its contact i 1 via the corresponding head contacts IIu6 and II o5. Another signaling possibility is given when the upper or lower head contacts of all tap changers I to III are operated in the adjustment position, so that the control direct current has dropped below a certain limit, which is indicated by the auxiliary relay G (Fig. 1). In this case, as shown in Fig. 3, a display device L2 is expediently via a break contact g and via the lower or upper head contacts I u 3, II κ 3, III 2 (4 or Io3, II0 4, IIIo4 of the tap changer I, II, III are connected to a voltage source in order to display the adjustment achieved in this extreme setting. The mechanics of the stepping mechanisms are preferably designed so that after switching on a control pulse sent by the pulse generator G, the step switch turns fully to the next position, even when switching In the sense of the present invention, both a step-by-step circular switching movement of an operating axis and, in particular, a straight switching movement of a tuning means can be derived from the movement of the individual stepping mechanisms B. Touch or measuring probes, short-circuit piston, etc.) are understood. A more extensive automation of the measuring process within the meaning of the invention can be achieved in that, for example, type wheels are applied to the axles that are assigned to the individual tap changers and, after the normal has been set, print a number corresponding to the respective set control stage of their tap changer, so that the Adjustment value or the measurement result can preferably be read on a paper strip in the form of a printed number. Patent claims: 1. Circuit arrangement for the automatic adjustment of a measuring circuit using a by means of several step switches, preferably decadically adjustable normal, with each Step switch is assigned a forward or backward step-by-step switch, which is controlled via suitable, in Dependent on one by means of its size and polarity the amount and the direction of the misalignment indicating DC control voltage operated switching devices to a common pulse generator can be switched on and at the switching elements in the connecting lines of the stepping mechanisms are arranged to the pulse generator, characterized in that they belong to the switching elements Switching means are direction-dependent and influenced by the DC control voltage and have several size-graded response thresholds and that the switching elements are arranged in such a way are that depending on the greatest response threshold exceeded in each case specific step switch assigned to this with the selected depending on the polarity Stepping mechanism is switched through to the pulse generator. 2. Circuit arrangement according to claim 1, characterized in that each stepping mechanism a control relay is assigned, its arranged in the connection line to the pulse generator The contact is used to switch the stepping mechanism through to the pulse generator. 3. Circuit arrangement according to claim 1 or 2, characterized in that the excitation circuits for those belonging to the forward and backward stepping mechanism of a tap changer Control relay optionally via the contacts of a step switch assigned to this, from the Control DC voltage influenced, polarized relay are closed, which one of the Has the order of magnitude of the relevant step unit corresponding response current value. 4. Circuit arrangement according to claim 3, characterized in that the polarized by a Relay-dependent control relay contacts in the lower response current values of the polarized relays have dependent excitation circuits, which interrupt them when excited. 5. Circuit arrangement according to claim 1 or 2, characterized in that as a direction-dependent, Switching means with response thresholds graded in terms of size, a common for all control relays from the DC control voltage influenced, polarized step relay, which is used in the excitation circuits of the Control relay has arranged contacts that depend on the size and polarity of the DC control voltage can be actuated. 6. Circuit arrangement according to claim 5, characterized in that the to a certain The contact belonging to the excitation level of the polarized step relay is assigned additional contacts,