SU932313A1 - Device for measuring pressure - Google Patents

Description

(54) DEVICE FOR MEASURING PRESSURE

one

The invention relates to instrument making and can be used to measure the pressure and temperature of liquid and gaseous gases.

Devices for measuring forces and pressures are known that use magnetically elastic force transducers to output frequency 1.

Closest to the present invention is a device for measuring forces comprising a magnet guide with excitation windings and a measuring winding included in a self-excited multivibrator circuit 2,

The known device does not allow a force or pressure measurement add-on. measure temperature as well.

The purpose of the invention is to provide simultaneous temperature measurement.

This goal is achieved by the fact that the device is equipped with a clock generator and a computing unit, the first input of which is connected to the output of the multivibrator, and its second input and control input of the source of the basic offset of the multivibrator are connected to the output of the clock generator.

FIG. I shows the general scheme of the device; Fig 2 is a diagram of its computing unit; in fig. 3 shows the design of a magcioelastic sensor.

The device (Fig. 1) contains a magneto-elastic sensor I, included in a magnetic self-oscillating multivibrator 2 with a base bias source 3, a computing unit 4, the first input of which is connected to the multivibrator output and a clock generator 5 whose output is connected the second input of the computing unit and the control input of the 6ai3C oro displacement source of the maonitic multivibrator.

In the diagram (Fig. 2), the computing unit contains two two-input keys 6, built on the basis of logic circuits AND, the first inputs of which are connected to the output of the multivibrator, and the second - to the clock generator, four analogs of 39 automatic avi-keys 7, Darview, inputs of the first and the third of which is connected to the output of the first key 6, and the first time the second and fourth keys of the second key 6, the second inputs of all the keys 7 are connected to the outputs of the block 8 time intervals associated with the clock generator. In addition, the outputs of the first and second 7 are connected to the summing and subtracting inputs of the reversible counter 9, and the outputs of the third and fourth klyochei 7 are connected to the inputs of the reversible counter Y. The number of the code contained in the counter 9 carries information about the pressure P, and the value of the Code contained in the counter 10, carries information about the temperature T. The sensor depicted (FIG. 3) of the magnetoelastic contains a ferromagnetic body 11 with a membrane 12 having a hard center 13 on which the winding K 14 of the transducer is made. on one common to atush | The ferromagnetic plate 15, reinforced with a ring 16 on the bottom of the hull protrusion, together with a membrane and a rigid center forms a closed magnetop {: gadfly. The device is working in the way. In working condition, the membrane 12 of the magnetoelastic sensor 1 is affected by pressure P and temperature T. This leads to its deformation and change of the magnetic direct current of the map and the ground conductor, which leads to a change in the frequency of oscillations of the multivibrator F (P, T ) (} The signal from the output of the clock generator changes the basic bias of the multivibrator, which leads to a change in the functional and intrusiveness (1). At this, at each of the two voltage values at the output of the clock generator, the transducer characteristic vanilla {I remains {virtually linear. Then, provided that the coefficient of independence of -C and -d | is independent, in a defined interval of P and T for each half-cycle of the clock signal, respectively, we have at the output of the multivibrator 2.T WHpp TT where, K ,, K - Sensitivity coefficients for pressure and temperature134 in the first and second half-periods of the clock signal; the corresponding initial values of the frequency of the multivibrator 2; Next, the signal from the output of the magnetic multivibrator 2 is fed to the first input of the computing unit 4, on the sec second input of which is to provide a solution of (2) is also supplied takte® and the frequency f. Solution (2) has the form .b, Tzajft + a f brj, g, l. Р iP -Т- г-V-V- - ц. o / gp V-ad V lZ 1p Coefficients, K, and initial frequencies of Og are determined experimentally, and then (4) are used to calculate the coefficients of system (3), the last two of which are L-, and bj are pre-entered into reversible counters 9 and Ur, respectively, as initial values of P and T. The block 8 of time intervals gives four second impulses to the second inputs of keys 7, each of which has the proportion of proportional signals q, qrj, a, and, respectively, simultaneously with the formation of these im1; 0glsov when exposed to a clock signal f at its first loop through one of the keys 6 to the first inputs of the first and third keys 7 receives a signal with frequency f, and the second half-code clock frequency through the second key 6 to the first inputs of the second and fourth keys 7 receives a signal with frequency fij. In this case, at the output of the first key 7, we obtain a sequence of groups of pulses with the following frequency in groups 5 and d; the accuracy of these groups is equal, at the output of the second key 7 - respectively, with the frequency fn and duration, at the output of the third key 7 - with the frequency and duration q, and the output of the fourth 0-jjfij, respectively. Pairing the supply of these sequences to the inputs of two reversible counters 9 and Yu, as shown by the HSI of FIG. 2, provides a solution to the system (3) in the form of binary pressure codes P at the output of the reversible counter 9 and temperature T at the output of the reversible counter Yu,

Due to the timely measurement of the flooding and the temperature of the proposed device, the required ns menclatura of the sensors is reduced and the point r increases (pressure measurements are measured. The device is easily matched with digital information processing systems.

Claims (2)

1. USSR author's certificate number 571.714, to l. q 01 U 1/12. 1976. 2. Authors certificate of the USSR. No. 324522, cl. From O1 U 1/12, 1969. BUT /, l Oifi QI dz Off g 0h fi Oif Osft 03 fig.g