SU1727082A1 - Device for monitoring belt conveyer speed - Google Patents

Abstract

The invention relates to an instrumentation technique and can be used to control speed limits. The aim of the invention is to increase accuracy and reliability. The goal is achieved due to the fact that the controlled angular rotation speed is set by the first key 7, and the angular speed of the slip is controlled by the second key 8. Changing the frequency of the output signal of the sensor 2 leads to switching with keys 7, 8, 9 of counter 3. 2 Il.

Description

The invention relates to a measuring and control technique and can be used to control speed limits, in particular, slippage of a belt conveyor.

A device for controlling speed is known, which contains a reference frequency generator, a pulse speed sensor, a speed counter, an RS flip-flop and a circuit I.

A disadvantage of the known device is low reliability in controlling deviations of the measured speed.

The closest to the invention in technical essence and the achieved result is a device comprising a reference frequency generator, a pulse speed sensor, a speed counter, first and second decoders, a slip counter, first and second RS-triggers, elements I.

The drawback of the device is the low reliability and accuracy of the slip measurement.

The reliability of the device is determined by the elements entering into it. In particular, the switches included in the device significantly reduce the reliability of the device as a whole.

As for the measurement accuracy, it is determined by the frequency of the reference frequency generator, but the frequency of the generator is unchanged when measuring the nominal speed of rotation of the drive and when measuring slip, where higher measurement accuracy is needed, i.e. higher frequency. Moreover, there is no need for a second counter and a decoder, since a single counter and a decoder are sufficient to signal a given deviation of the rotational speed from the nominal one.

The aim of the invention is to improve the accuracy and reliability of the device.

The goal is achieved by the fact that in a known device for controlling the speed of a belt conveyor containing a reference frequency generator, a pulsed

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speed sensor, counter, switch, first RS flip-flop, second RS flip-flop, the output of which is the device output, R-inputs of the flip-flops are combined and connected to the output of the pulse speed sensor, the output of the reference frequency generator is connected to the counting input of the counter, whose outputs are connected via a decoder to the switch inputs, a normally closed first key, a normally open second and third keys, an OR element, an output connected to the meter's installation input, and a pulse driver are added, and you the stroke of which is connected to the first input of the OR element, the second input of the OR element is connected to the reset input of the first and second RS-flip-flops and the output of the pulse speed sensor, the S-inputs of the first and second RS-flip-flops are connected respectively via the first and second keys to the first and the second outputs of the switch, and each of the outputs is connected to a reference of the third key, the output of the first RS-flip-flop is connected to the control input of the first, second and third keys and the pulse driver.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - a scheme explaining the mechanism for increasing the frequency of the generator when it is switched by the switch key.

The device contains a reference frequency generator 1, a pulse speed sensor 2, a pulse counter 3, a decoder 4, the first RS flip-flop 5, a switch 6, which selects the corresponding outputs of the decoder, the first, second, third keys 7, 8, 9, element OR 10, a pulse shaper 11, a second RS flip-flop 12, a capacitor 13, a resistor 14.

The device works as follows.

The controlled angular speed of the belt conveyor (i.e., the time of one revolution of the drive shaft) is set by the first key 7, and the angular speed of the slip by the second key 8. The pulses from the sensor 2 are fed to the reset inputs of the first and second RS-triggers 5 and 12 and the element OR 10 is input to the reset input of the pulse counter 3. If the angular velocity lies in the range of speeds set by the first and second keys 7, 8, the RS flip-flop 12 is in the off state. Counter 3 and RS-flip-flops 5 and 12 are zeroed by pulses of the transmitter 2 at each revolution of the belt conveyor shaft. If the angular velocity of the shaft decreases, then at the moment the RS trigger 4 is switched on, the keys 7, 8, 9 simultaneously switch, i.e. the keys 8 and 9 are closed and the key 7 is opened, the counter 3 is reset. In this case, the frequency of the counter 3 increases (for example, 10 times) and, accordingly, the slip counting begins with greater accuracy. If the amount of slip is less than the set one, then the pulse from sensor 2 will reset RS-flip-flop 5 and reset counter 3. If the amount of slip exceeds the set-point, then via key 8 the signal from the second output of switch 6 goes to the setup input of RS-flip-flop 12, the trigger is activated, signaling about slipping. The trigger 12 will return to its initial state by the signal from the transmitter 2.

FIG. 2 shows one of the possible generator circuits 1 and the connection of the key 9, the switching of which allows the generator frequencies to be increased a certain number of times.

The proposed device for controlling the speed of a belt conveyor improves the reliability of the device and the accuracy of measuring the slippage of the monitored shaft, which will lead to an increase in the reliability of the aggregates, for example, the mass preparation compartment as a whole.

Claims (1)

Apparatus of the Invention A device for monitoring the speed of a belt conveyor, comprising a reference frequency generator, a pulse speed sensor, a counter, a switch, a first RS flip-flop, a second RS flip-flop, the output of which is a device output, the R inputs of the flip-flops combined and connected to the pulse output speed sensor, the output of the reference frequency generator is connected to the counter input of the counter, the outputs of which are connected via a decoder to the switch inputs, characterized in that, in order to increase accuracy and reliability, into it In addition, a normally closed first key, a normally open second and third keys, an OR element, an output connected to the installation input of the counter, and a pulse shaper, the output of which is connected to the first input of the OR element, the second input of the OR element, are connected to the reset input of the first and second RS- the flip-flops and the output of the pulse speed sensor, the S-inputs of the first and second RS-flip-flops are connected respectively to the first and second outputs of the switch, and each of the outputs is the master circuit frequency of the reference frequency generator is connected to its third switch contact, RS- output of the first flip-flop is connected to the control input of the first, second and third keys and entry pulse shaper.