SU1075171A1 - Oscilloscopic galvanometer adjustment method - Google Patents

Abstract

A METHOD FOR SETTING AN OXYCHEGRAPHIC GALVANOMETER, which includes applying a permanent magnetic field to the moving part of the galvanometer, passing an alternating current through it, detecting the deviation of the light spot from the galvanometer mirror and fixing the position of the movable part, differing in the definition of the moving part, and because, in order to detect the light of the galvanometer, the position of the movable part differs from that, with the aim of detecting the light of the galvanometer and fixing the position of the movable part, with the aim of detecting the light of the galvanometer and distinguishing the position of the movable part, with the purpose of detecting the light of the galvanometer and fixing the position of the movable part, with the aim of detecting the light of the galvanometer and distinguishing the position of the movable part, with the purpose of detecting the light of the galvanometer and fixing the position of the movable part, and with the aim of detecting the moving part of the movable part, with the aim of looking at the galvanometer during the action of a magnetic field while passing an alternating current through the galvanometer winding, the deviation of the light spot from the galvanometer mirror to both sides of it the initial position, the phase of the alternating current is changed by 180, and the indicated deviation is recorded, after which simultaneously with the transmission of alternating current through the jersey of the transducer, a constant current is passed, the amplitude of which is monotonously increased, and the deviation of the light is again recorded during the passage of direct current in both directions from the initial position, stop the increase in the amplitude of the direct current at the moment when the current asymmetry value of the galvanometer is zero, and then stop. The alternating current, the fixation of the position of the movable part is produced by passing a direct current, and the current asymmetry value of the galvanometer and the amplitude value of the alternating current are determined from the following relations (, ohgG tt-at i (L where 3 is the amplitude value of the alternating current / С in- - the current value of the asymmetry of the galvanometer; accordingly, the current deviations of the light spot on both sides of the initial position; P the value of the deviation to both sides of the zero direct current and alternating current of the joint venture with zero phase shift; the same deviations when shifting the 10.20 phase of the alternating current to 180; S is the sensitivity of the oscillographic galvanometer; a - gradient deviation of the galvanometer.

Description

The invention relates to a measurement technique and can be used when setting up oscillographic galvanometers (FG) in order to reduce the errors of the latter. A known method of adjusting the exhaust gas includes adjustable movement of the holders of the movable part, recording its position through viewing windows in the slots of the exhaust casing and fixing the position of the movable part L. The disadvantage of this method is the impossibility of adjusting the position of the frame in a direction perpendicular to the plane of the frame. In addition, the viewing windows violate the tightness of the hull, therefore it is not applicable to exhaust gas with fluid handling. A known method for setting up an exhaust gas assembly includes applying a constant magnetic field to the moving part of the exhaust gas, passing the alternating current through the winding of the galvanometer, determining the positions of contact of the body with the moving part by offsetting the light spot from the mirror and fixing it at the middle part between the positions of tangency 2. The disadvantage of this method is that it does not ensure that the plane of the frame of the movable part is correctly positioned relative to the magnetic induction vector, the angle between which determines the difference in deviations of the spot light from the zero position when the polarity of the current changes, the asymmetry that is part of the error registration. The purpose of the invention is to improve the accuracy of the setting. This goal is achieved by the method of setting up an oscillographic galvanometer, which includes applying a constant magnetic field to the moving part of the galvanometer, passing an alternating current through it, detecting the deviation of the light spot from the mirror of the galvanometer and fixing the position of the moving part during the action alternating current through the galvanometer winding register the deviation of the light spot from the galvanometer mirror to both sides of its initial position, changing The phase of the alternating current is 180 °, and the indicated deviation is recorded, after what simultaneously with the passage of the alternating current a direct current is passed through the winding of the galvanometer, the amplitude of which is monotonously increased, and during the passage of direct current again (the deviation of the spot light is recorded both sides of the initial position, stop increasing the amplitude of the CONSTANT current at the moment when the current asymmetry value of the galvanometer is zero, and then the transmission of alternating current is stopped, The fixing of the position of the movable part is performed by passing a direct current, and the current asymmetry value of the galvanometer and the amplitude value of the alternating current are determined from the following relations (. 0-n7oVC tO- 20 U, -vi,, peak value of alternating current; LPD - the current value of the asymmetry of the galvanometer, respectively, the current values of the deviation of the spot spot to both sides from the initial position; deviation values in both directions at zero direct current and alternating current with zero fBy shift; iO 2o AC phase difference of 180 °; S - exhaust sensitivity; a - calibration deviation of the galvanometer. The drawing shows a diagram of an apparatus for carrying out the proposed method. The device contains a generator 1. alternating current, switches 2 and 3, potentiometers 4 and 5, DC source 6, switch 7, milliammeter 8, adjustable exhaust 9, light source 10 and screen 11. The method is implemented as follows. The galvanometer 9 is installed in the socket of the magnetic unit (not shown) and the beam of the source 10 of the light 10 reflected to the screen 11 is reflected by the exhaust gas reflected by the mirror. This position is taken as the initial one. Switches 2 and 3 are turned on. Generator 1 on EXT 9 provides a variable signal, which is, for example, a series of square impulses, so that the screen receives light from the line with a pronounced thickening corresponding to the initial position. Potentiometer 5 sets the amplitude of the alternating current according to expression (2), which ensures maximum accuracy of recording the current asymmetry value, after which the difference between the deviations to the left and right of the initial position (n, R) is determined. Then switch 2 changes the phase of the alternating current to the opposite one and again determines the asymmetry (), at a value of yLog / different from :: ul, close key 7 and gradually enter potentiometer 4 until the zero position is shifted on the screen 11 by 10-12 mm. If the value increases during the adjustment process, change the direction of the direct current with the switch 3. The amplitude of the constant current is increased by using potentiometer 4 until the position of the true zero is found, at which (. Different zero and winding plane galvanometer parallel to the vector of magnetic induction.

This position of the movable part of the exhaust gas is fixed and fixed the movable part in the galvanometer housing.

The proposed method allows not only to avoid mechanical contact of the moving part and the exhaust housing, but also to improve the accuracy of the moving part relative to the magnetic induction vector and thereby increase the registration accuracy by reducing the error from the asymmetrical deviation of the moving part.

Thus, the static error of registration is determined by the difference between the real current characteristic and the ideal one, which is a direct proportional relationship between the magnitude of the input signal and the deviation of the light spot of the oscillographic galvanometer on the recording media.

The real current characteristic depends on the relative position of the frame of the moving part of the exhaust gas and the magnetic induction vector, on the optics of the galvanometer and the oscilloscope. For galvanometers, in the case of which there are pole inserts, the actual current characteristic can be written as follows

- CH4- 1)

where T is the current through the exhaust winding;

li - optical lever;

GO is the deviation of the light spot on the de-energized exhaust gas screen from the position of the true zero.

It follows from formula (3) that the real current characteristic is closest to the ideal one in the case that. the light spot of the de-energized galvanometer corresponds to true zero. Determining this position of the light spot is reduced to determining the position at which the current deviation becomes symmetrical when its polarity changes, i.e. the condition when in the equation (3) there is no term ±.

I

According to the proposed

way asymmetry deviations sv, dits to zero. As follows from equation (3), this method reduces

This is also the nonlinearity of the current characteristic, since for non-linearity it is determined only by the last member of the equation. When assembling the exhaust gas by

To the proposed method, the systematic static error of the registration of the light-beam oscilloscope, which is associated with the asymmetry of the deviation of the exhaust gas and the nonlinearity of its current characteristics, does not exceed 1% for deviations of about 50 mm.

Claims (1)

METHOD FOR SETTING oscillographic galvanometer comprising exposing a constant magnetic field on the movable part of the galvanometer variable transmittance therethrough ¹ Nogo current deviation of the light spot on the recording galvanometer mirror and fixing the position of the movable part, characterized schiys I that, in order to increase the accuracy of adjustment, in the process of exposure to a magnetic field when passing alternating current through the winding of the galvanometer, the deviation of the light spot from the mirror of the galvanometer is recorded on both sides of its initial th position change AC phase 180 ^e, as well as recorded above deviation, and then simultaneously with passing an alternating current through yubmotku galvanometer passed; constant current, the amplitude of which (monotonously increases, and in the process of DC transmission again recorded deviation of the light spot in both sides of the initial position, stop increasing the amplitude of the direct current at the moment the current value of the asymmetry of the galvanometer is zero, and then stop. ennogo current, wherein the fixing position of the movable part produced by passing a constant current, and current value of asymmetry of the galvanometer and the amplitude value of the alternating current is determined from the following relations ^ ^P 0r = \ ^'r' 1t ^'n 2tU 2 * a_ and wherein 3 ~ amplitude value alternating current; - the current value of the asymmetry of the galvanometer; accordingly, the current values of the deflection of the light spot on both sides of the initial position; side deviation values at zero rated current and alternating current with zero phase shift; the same phase deviations of variable number 180; sensitivity of the physical galvanometer; calibration deviation of the galvanometer. .t'Rgtot at ^<n o 2o ^η; · ΐο both at a current offset Rav SU („107517Д <i α) ι go