SU605198A2 - Long time interval measuring device - Google Patents

Description

The invention relates to the field of automation and can be used in automation devices, in particular in automatic systems for monitoring, controlling and predicting the technical condition of monitored objects.

Devices for measuring long time intervals are known, comprising threshold circuits, a transducer, and a pulse number counter of the reference generator 1.

The disadvantages of devices of this type include relatively poor noise immunity with respect to interference signals.

According to the main author. St. No. 508777, a device for measuring long time intervals is known, comprising a series-connected photocell, a low-current relay, a pulse shaper, a pulse counter, logic AND, a decoder, and an indicator 2.

However, when the luminous flux fluctuates relative to the level of the low-current relay triggered, for example, by a brief rain, fog, smoke, a false pulse will be introduced into the pulse counter, which will lead to a measurement error of the time interval.

The purpose of the invention is to increase the noise immunity and expand the dynamic range.

For this, additional normally open contacts to the low-current relay and a resistance connected in series with the winding of the low-current relay are introduced, with additional normally open contacts connected in parallel with this resistance.

The drawing shows a block diagram of a device for measuring long intervals.

time, containing photocell 1, low current relay 2, relay 3 times, driver 4 pulses, counter 5 pulses, block 6 of logic circuits AND, decoder 7, indicator 8, electromagnetic relay 9, normal

open contact 10 of low-current relay, resistor 11, normally open contacts 12 and 13 of the electromagnetic relay, input 14 of the "End of measurement" signal and input 15 of the computing device.

The unit of time in the proposed device is day. The principle of operation of the device is based on the use of changes in natural light when changing day and night. Photocell 1 used in

device that works as a converter of light energy into electricity. The electric current generated by the photocell flows through the winding of the low-current relay 2. The current value is proportional to the illumination

photocell, limited by resistor II,

The low current relay 2 operates in the case when the amount of current flowing through its winding becomes equal to or greater than the value of the operation current. The magnitude of the relay operation current is chosen such that the relay operates reliably on the darkest day.

When the relay 2 trips, its contact 10 closes, which closes the power supply circuit of the electromagnetic relay 9. The contact 12 of the relay 9 shunts the resistor 11, which will lead to an increase in the current in the winding of the low-current relay 2 and its safe keeping in the on state even when fluctuation of the light flux caused, for example, by a short rain, fog or smoke. A normally open contact 13 of the electromagnetic relay 9 connects the power supply bus to the relay 3 times, which is triggered after a certain time D after the closure of contact 13. The magnitude of the delay A is chosen so that it is not less than the maximum duration of the light flash interference. The change in the amount of delay A is dried, adjusted by the time relay 3. When triggered, the relay 3 produces a signal to the pulse shaper 4, which produces a pulse of a certain polarity, amplitude and duration, which is mixed with respect to the moment the electromagnetic relay responds by the amount of delay Af. This pulse is applied to the input of the counter 5 pulses. As a result, one will be added to the contents of the counter.

When the photocell luminance decreases, the current flowing through the winding of the low-current relay 2 decreases. When the current reaches a value equal to or less than the release current of the relay, relay 2 opens its contact 10 and disconnects the power bus from the winding of the electromagnetic relay 9. The circuit returns to its initial state . The release current of the low-current relay 2 is selected such that the relay reliably releases on the brightest night.

After one day, the described process is repeated. Thus, once every day, one is added to the contents of the pulse counter 5. Consequently, the contents of the counter are the current value of the measured time interval.

If the pulse counter is binary, its contents are represented in binary code. A single output of each pulse counter 5 pulses through the logic circuit AND is connected to the input of the decoder 7. When a signal arrives at input 14 "The end of measurement, the outputs of those logic circuits AND block 6, which are connected to the excited single outputs of pulse counter 5, are excited A decoder 7 is supplied with a combination of signals corresponding to the contents of the pulse counter. The decoder 7 converts binary to decimal. As a result, the indicator 8 displays the contents of the pulse counter in the form of a decimal number. By the signal "End of measurements, the contents of the counter can be, for example, automatically fed to the input of the computing device 15, from which it is possible to predict the technical condition of a certain object.

Claims (2)

Invention Formula Device for measuring long time intervals by aut. St. No. 508777, characterized in that, in order to increase noise immunity and expand the dynamic range, it additionally introduces normally open contacts to low-current relay n resistance connected in series with the winding of the low-current relay, with additional normally open contacts connected in parallel with this resistance. Information sources, taken into consideration during the examination 1. Shlolnsky V. A., Chernin V. N. Electrical devices of time. M., “Energia, 1934, p. 73. 2. USSR author's certificate No. 508777, cl. G 04F 10/04, 1974.