SU720559A2 - Photo relay - Google Patents

Description

one

The invention relates to the field of electro-automatic elements and can be used in automatic control systems with the quality of a photo sensor for detecting a light flux.

Known according to author's certificate N 4416О8 device containing a photodetector, Schmidt trigger, one-shot, NOT and AND logic circuits, the one-shot input connected to the Schmidt trigger output, one input of the AND circuit connected to the input of the Schmidt trigger, and the second through the NOT circuit to the input cascade odiovibrator.

A disadvantage of the known device is that in the presence of a stationary stochastic light interference, the average value of the useful signal at the photoelectric output decreases, which leads to a decrease in the measurement accuracy of the information content of the luminous flux. This occurs 3 due to the restriction of the luminous flux of interference by the Schmidt trutter, the threshold of which is set to

taking into account the average value of the stationary stochastic light interference.

The aim of the invention is to improve the accuracy of recording changes in the light information flow when exposed to a stationary stochastic light interference.

For this, the photo relay additionally contains a relay element. And connected in series between the personal | 1st link with the dead zone and the integrator, the inputs of the relay element and the link with the dead zone are connected to the Schmidt trigger input, the output of the integrator is connected to the output cell of the photo relay and through the open contact of the relay element - with its own entrance. By connecting the integrator to the photodetector output, through a deadband link, the part of the photodetector output signal that has not been worked out by the Schmidt trigger is integrated. On command from the relay element, the integrator is discharged and its discharge signal is summed at the inputs of the jau- cell of the photo relay. The output cell of the photorelay is more in the on state, which makes it possible to increase the average value of the output signal of the photorelay and thereby compensate for the negative effect of light interference on the accuracy of the photorelay. FIG. 1-2 - invented the proposed relay; FIG. 3 - diagrams of device signals. The photo relay contains a photodetector 1, Schmidt trigger 2, the threshold. and which is set taking into account the average :) value of the stationary stochastic interference, one-shot 3, logic circuitry 4 and 4, respectively, output cell 6 photo relay, for example, a two-winding relay; relay element 7, the threshold of which the vanity is equal to the threshold that was triggered and J of Schmidt trigger 2 link 8 with a zone, insensitivity equal to normal and Schmidt trigger trigger threshold, breaker contact 10 of the relay element, inputs 11-12 of the logic circuit 5, semiconducting Triodes 13-17 (transistors) of the p-ia-p type of Schmidt trigger, one-shot 3 and NOT logic, diversified RC circuit 18-19, 2O-21, diodes 22-24, resistor 25 and capacitor 26 of the time delay circuit of the one-shot 3 The output of the photodetector 1 is connected to the trigger inputs 2 Shm Idta, relay element 7 and link 8 with dead zone. The collector of the first triode of the Schmidt trigger is connected to input 12 of the logic circuit 5, input 11 of which is connected through the logic circuit of HE 4 and the single-oscillator 3 to the collector of the second triode of Schmidt trigger, the output of the logic circuit 5 is connected to one input of the output cell of the photo relay 6 the input of which is connected to the output of the integrator E, in the feedback circuit of which the disconnecting contact 10 of the relay element 7 is connected. The output of the link with the dead zone is connected to the input of the integrator 9. The photo relay works as follows; The total luminous flux Fg: consisting of the arithmetic sum of the useful (information-luminous luminous flux f) and the stationary stochastic coupling noise, for example, of harmonic type (Fig. 3}, goes to the photodetector 1 (Fig. 1 and 2). With a change in the light flux flux FZ: the Schmidt trigger is triggered below the defined voltage U. The negative collector of the first transistor of the trigger increases and the second transistor decreases. In this case, the RC chain 1819 forms a short positive pulse which through diode 22 goes to the transistor base After the time delay, determined by RC-chain 25 and 26, the one-vibration 3 returns to the original oscillation. Transistor 15 reopens, and RC 2O-21 generates a short positive pulse, which through a diode 23 and the NOT 4 circuit assembled on the transistor 17 is fed to the input 11 of the circuit AND 5. To the input 12 of the circuit AND 5 a negative collector voltage of the transistor 13 is applied. IF by the time the negative pulse arrives at the input 11 of the circuit AND 5, the transistor 13 remains closed, then the circuit And 5 works and gives sig al to an output cell (two-winding relay element) 6. Due to the delay in triggering the monostable 3 The selection of interference is provided for its duration. Interference, the period of change of which is less than the constant time of the one-shot 3, does not cause false triggering of the photo relay. However, in the presence of light interference, the average value of the information luminous flux at the photorelay output decreases due to the fact that the Schmidt trigger is a threshold element, i.e. element with saturation (restriction). When there exists at its input a total signal consisting of a slowly varying component Φ and a stationary stochastic field L (IF. Mecha Φ, the average value of slow OOf it of the varying component F output I IIF / signal of a Schmidt trigger (. Element saturation decreases). The light interference clogs the useful signal, the accuracy of registration of the change in the useful light flux of the photorelay is measured. To eliminate this error, integrator 9 integrates that part of the output signal of the photodetector 1 that exceeds Shmidt trigger trigger rat. At the moment Schmidt trigger triggers, relay element 7, which, with its normally closed contact Y, turns on the integrator 9. A photo detector from the output a comes through the link with the dead zone at the integrator 9. Link 8 consists of a diode 24, a variable resistor, a DC source and an operational amplifier, Simultaneously used for the integrator 9, the value of the deadband is selected with the help of a variable resistor and the selection of the voltage value of the direct current point of block 8 so that integrator 9 integrates a signal proportional to the limited (cut off) part of the output signal of photodetector 1 During the time when Schmidt’s trigger is in an unstable state, integrator 9 integrates that part of the output signal of photodetector 1 that exceeds the level U - Schmidt trigger trigger level. When the luminous flux changes below the level and the photodetector output signal leaves the Schmidt trigger saturation zone, Schmidt trigger and relay element 7 return to initial state. The opening contact 10. The relay element 7 closes. Integrator 9 begins to discharge according to aperiodic law. The discharge signal of the integrator 9 is fed to the second winding of the double-winding relay of the output cell b. During the discharge of the integrator 9, the output cell 6 is in the ac state. The additional delay time of the output cell 6 is directly proportional to the size of the limited part of the output signal of the photodetector 1. By introducing the delay, the average value of the output signal is compensated for and the negative influence of the light interference is compensated, resulting in an increase in the registration accuracy of the change in useful light flux under steady-state stochastic light conditions interference whose parameters are close to the parameters of the useful luminous flux, provided that the amplitude of the signal of the useful light is eye and the average value of the light-interference set. Rumula of the invention of the Photorelay by the author. St. No. 4416О8, characterized in that, in order to measure the accuracy of measuring the information luminous flux in the presence of a stationary light disturbance, it additionally contains a relay element and an integrator, a relay-element, and a link with a dead zone are connected in series with each other to the input of the Schmidt trigger, the integrator output is connected to the input of the output photocell photocell and, via a normally open break contactIX) element, to its input.

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Claims (1)

Claim Photo relay St. No. 441608, characterized in that, in order to improve the accuracy of measuring the information luminous flux in the presence of stationary light interference, it further comprises a relay element and a link to the dead band and an integrator, inputs of the relay element connected in series. And links with the dead zone the input of the Schmidt trigger, the integrator output is connected to the input of the output cell of the photorelay and, through the opening contact of the relay element, with its input. ΡίίΖ, Ι 72055 $ TSIIIPI Order 10233/41 Draw 844 Subscription Branch of PPP Patent, Uzhhorod, st. Project, 4