SU842590A2 - Method of automatic balancing of ac zero measuring circuits - Google Patents

Description

The implementation of this method extends to measuring circuits, in which the ratios between the scales of regulatory actions, which are determined by the sensitivity of the measuring circuit to a single change in the controlled parameters, are close to unity. In this case, the angles that define the areas of the fault are quite large, which simplifies the technical implementation of this method. The disadvantage of this method is that when measuring the relative parameter of the impedance, for example, tgd or tg V, the relative parameter sensitivity can vary by order, since the main parameter varies within the measurement subrange by 10 times. This leads to a re- narrowing of the error zone with respect to the relative parameter, which makes it impossible to use it to automate such schemes. The purpose of the invention is to provide the possibility of measuring the relative parameter of the complex resistance by equalizing the scales of regulating influences when balancing measuring circuits with substantially different sensitivities. -organs signs of the deviation of the controlled parameters from the equilibrium state by the second parameter, where the second pa The meter starts to commute with a weight determined by the number of the next non-switched weight by the first parameter, if after the last switching of the first parameter by the second parameter, the specified zone went out with the enacc, corresponding to the underbalance sign, in the case of the second the parameter is dropped and its subsequent weights are included, corresponding to the switched weights in the first parameter, the correspondence of the switched elements of the chain, which has a larger scale of regulating influences elements of the second chain are set, starting with the element of the first chain that remains switched on or leads to the error zone for this chain, and with control signals at the beginning of the balance indicating simultaneous switching, the first element of the second chain is also included, and decisions about the included element are made after the correspondence of the elements of the adjustable chains is established; With signals for the initial switching of only the first chain, adjustment of the elements of the second chain is made, starting with the second element after matching. FIG. Figure 1 shows a topographic diagram of the measurement circuit, explaining the measurement features of the relative impedance parameter, due to the variable sensitivity of the measurement circuit. FIG. 2 and 3 illustrate the essence of the method of equalizing the scale of regulatory actions, in FIG. 4 shows a block diagram of a device implementing the method in question. FIG. 2 shows how the correspondence of the elements of the chains P and q with weighting factors of 8–4–2–1 for a particular case with p 1 and p 10 should be, and FIG. 3 - practical The establishment of correspondence between the elements using the proposed method for any value of p is from 1 to 10. As can be seen from FIG. 2, for the presented cases, the most accurate alignment of the scales of regulatory actions takes place, since a single change in the parameter p causes the same change in the imbalance signal as a single change in the parameter q as for p 1, and so for p 10. Because the practical implementation of the matching elements of the chains p and q require knowledge of the value of the parameter p, the parameter p first commute. If, the correspondence is established, starting with the element p 8, since after its switching this weight either remains switched on or its inclusion results in the error zone with respect to the parameter p (Fig. 3a). At 8 p 4 for the same reasons, compliance is established, starting with the element p 4 (Fig. 3b); at 4 p 2 from element 2 (Fig. Sv); with 2 p5 1c of element 1 (Fig. 3g). Thus, the real case for p 1 differs from that shown in FIG. 2 in that the correspondence of the elements is established from the element p 1. For those shown in FIG. 3 cases, the ratio of weight coefficients, is kept equal to - 0.1 only for the variant Za. For options zb-zg ratio. Pi is not kept constant, but changes discretely depending on the switched weights., Taking the values for Fig, 36, 0.2; 0.125 at 4; for figs. Sv - 0,4; 0.25 with 2; for figs. Zg - 0.8; 0.5 with RMIN-

It is known that the smallest value of the angle g corresponds to the case of the smallest value of the term p. For those shown in FIG. 3 options, this value is 0.5, for which the minimum angle. The angle should not be greater than 13. If we consider that the error zone is determined by angle 1, then the maximum permissible phase instability in the worst case should not exceed .6-. For q "1 the angle increases to. + 6.5

To realize the phase stability of the path of the conversion of the unbalance signal into the control signal, which would meet these requirements, presents no technical difficulties.

Since the correspondence of the elements p and q is established after the inclusion of a certain element p, it is desirable, in order to eliminate the extra switching cycle, to decide on the first element in q, since the subsequent commutation of the elements p and q is performed simultaneously in accordance with the known prototype. For this, if control signals occur at the beginning of the balance, indicating that p and q are simultaneously switched, the first element p also includes q, but the decision on this element is made simultaneously with the p element, which establishes the correspondence between the p and q elements.

If at the beginning it is equal; The control signal indicates switching in the zone of errors in q, the first element in p that determines compliance also allows to establish the fact that its corresponding weight in q should be bypassed without switching, i.e. adjustment of q should start by skipping the first element.

The block diagram of the device implementing the proposed balancing method is shown in FIG. 4 contains a variable voltage generator 1; measuring circuit 2; unbalance signal amplifier 3 ;, shaper 4-Balance; shaper 5 reference stresses; triggers 6 and 7j, which form the switching characteristics of only one parameter (respectively, p and q); schemes 8 and 9 OR; one-shot 10; schemes II, 12 and 13 And; The trigger 14, the locking feature (underbalance, rebalance), which leaves the error zone, is based on a non-switched parameter; control unit 15, which forms clocks, pulses and ensures synchronization of operation of all units (CU); a trigger 16 defining a mode for establishing the correspondence of scales of regulatory actions; registers 17

and 18 measures (q and p, respectively), distributors 19 and 20 pulses (RI) -, distributor 21 pulse channels, allowing the passage of pulses in the RI 19, 20 alternately or simultaneously; auxiliary reversible counter, 22 fixing the number of clock pulses that have passed when switching only one parameter (in the error zone by another parameter); 23 high-frequency pulse generator; digital reporting device 24; initial start-up circuit 25.

Device works as follows. ,,

At the beginning of the balancing block, the initial start-up unit sets all the elements into their original state. Simultaneously with the connection of the first element of the chain p, a trigger 16 is triggered, which determines the mode of establishing the correspondence of the scales of regulatory actions. Trigger 16 also triggers the connection of the first element of the chain q, which is immediately reset, if trigger 6 is activated. If control signals indicate simultaneous switching of p and q, trigger 16 prohibits making a decision about the first weight on q.

Clock pulses from the CU through the circuit 9 are received only in RI 19 (for the parameter p). Switching the parameter p occurs before the appearance of the signal from block 4 - leave the weight on p or switch to switching only the parameter q (error zone on p). In this case, the trigger 16 is reset, whereby the prohibition of the passage of clock pulses in the RI 20, as well as in the pulse counter 22, is lifted.

The unit 21 directs the clock pulses either simultaneously in both the RIs 19 and 20, or alternately in the presence of signals from the flip-flops 6 or 7.

Suppose that the switching is performed only by the parameter p (in the error zone for q), in this case, the trigger 6 allows the clock to pass to the RI 19 and simultaneously to the counter 22. When the signal from block 4 is switched to the switching. Parameter q the one-shot 10 is excited , allowing the passage of pulses from the generator 23 N. and meter 22 and in blocks 21, 20.

At the same time, the simultaneous switching of the scales along q in accordance with the previously switched weights along p is provided.

Claims (2)

The decision on the included weights on q is determined by the state of the trigger 14. With underbalance, the previously included weights on q remain included, and the entire weights group on q, activated by pulses from block 23, is reset. Conversely, when rebalancing, the previously included weight in q is reset, and the above weight group is included. Similarly, the PSR is izvoditsya and switching weights on the parameter p, when leaving the zone, errors on p. The implementation of the proposed automatic balancing method reduces the number of balancing cycles in devices that measure the relative parameters of the impedance, bringing them almost to the value determined by the number of elements of the largest of the adjustable chains. The invention The method of automatic balancing, shivani zero measuring circuits of alternating current by the author. St. No. 72951 characterized in that, in order to make it possible to measure the relative parameter of the impedance by equalizing the scale of regulatory actions when balancing measuring circuits with significantly different sensitivity, the correspondence of the switched elements of the chain having a larger scale of regulatory influences is established by the elements of the second chain from the element of the first chain that was left on, or which led to errors in the zone for this chain, moreover, with signals at the beginning of equal balances, indicating simultaneous switching of elements of both chains, also commute the first element of the second chain, and making a decision about the included element is made after establishing compliance, and with signals for the initial switching only of the first chain, the adjustment of the second chain is performed from the second element. Sources of information taken into account in the examination 1. The USSR author's certificate 175125, cl. G 01 R 17/10, 1963. 2. USSR author's certificate number 729.517, cl. G 01 R 17/10, .1978. to h decade 19 decade 8 I 10.9 umm 0.9 0.4 0.2 0, G0.08 but I. 8 о .. г ч г г 0,8 o, f ,, MM. M t 0.8 0.1 0.2 01 2deKaSci where is scool 42 1 0.9 0.4 I M} T 0, oh oh, g 0,1 cfffS 0.8 Otf 0.2. g (rig.Z