SU1614123A1 - Device for monitoring line current of telegraph network - Google Patents

Abstract

The invention relates to communication technology. The purpose of the invention is to increase the reliability of the control. This is achieved by the fact that Schmidt triggers 15 and 16 are introduced as comparison devices, and also depending on the current in the circuit, the switch 17 is switched under the control action of the trigger 16. As a result, parallel to the resistor 1, which determines mainly the resistance devices of direct current, connects either a resistor 8 or a resistor 12, a resistor 7 and an LED 19 of the optocoupler 18. These circuits have equal resistance values, which allows to compensate for the change in current when the LED 19 is connected, depending on the values current in the monitored circuit. 1 il.

Description

The invention relates to communication technology, in particular to telegraph technology,

The purpose of the invention is to increase the reliability of control.

The drawing shows the electrical structural diagram of the device.

The telegraph network line current monitoring device contains first to twelfth resistors 1-12, first 13 and second 14 potentiometers, first 15 and second 16 Schmidt triggers, key 17, optocoupler 18, which includes LED 19 and a phototransistor pair 20, transistor 21, an indicator 22, zener diode 23, diode 24. The telegraph network 25, comprising a telegraph signal transmitter 26, a communication line 27, a telegraph signal receiver 28 and a variable resistor 29, is also shown in the drawing.

The device operates as follows.

When forming the transmitter 26 those; There is no current signal in the start line 27 and there is a high voltage log at the device output. 1.

When the Stop signal is generated, the current in the communication line 27 occurs abruptly. The magnitude of this current is set by the ohmic resistance of the communication line 27, input s; the resistance of the receiver 28 telegraph signals, a variable resistor 29, resistors 1.5 and equivalent resistances of the entire control device. In this case, one part of the equivalent resistance of the device is connected in parallel to both measuring resistors 1 and 5, and the second only to one of them, i.e. to resistor 1. Since resistors 1 and 5 are the most low-resistance ones at face value, and resistor 1 has a greater resistance than resistor 5, the voltage drop on the first one is also correspondingly larger than on the second one.

With an increase in the linear current, and, consequently, with an increase in the voltage drop across the measuring resistor 1, the key 17 opens and the resistor 8 is connected in parallel to the indicated resistor 1, which makes its total equivalent resistance decrease. A further increase in the linear current to a predetermined lower threshold or a certain excess thereof triggers the trigger 15. The lower threshold voltage is set by a certain position of the control tap of the potentiometer 13. This voltage must exceed the constant threshold voltage that is generated due to the zener diode. The operation of the trigger 16 leads to the locking of the key 17. In this case, the equivalent resistance of the trigger 16, the resistors 7 and 12 corresponds to the resistor 8. Therefore, the level of voltage drop across the resistor 1 remains unchanged at the moment of operation of the device at the lower current threshold.

As a result of the triggering of the trigger 16, a current flows abruptly through a resistor 7 and an optocoupler LED 19 19, which also leads to an abrupt opening of the phototransistor pair 20 of this optocoupler and transistor 21. Since the indicator 22 is connected in series with the phototransistor pair 20 of the optocoupler 12, it indicates a normal level current in the communication line 27. At the same time, a low voltage log appears at the output of the device. 0.

The response of the device to the upper threshold is fixed using the trigger 15 by the corresponding installation of the regulating tap of the potentiometer 13. A constant reference voltage, with which the current voltage value is compared, is also generated by the zener diode 23 and resistor 4.

So, with a further increase in the current in the communication line 2 by an amount equal to or slightly higher than the predetermined upper threshold of the device, the zero potential jumps at the output of the trigger 15, which leads to a decrease in the voltage level at the inverse input of the trigger 16, which returns to its original position . As a result of this, the current compensator (switch 17 and resistor 8) is switched back on and the level of voltage drop across the measuring resistor remains constant. When the trigger 15 is triggered, the indicator 22 turns off, 'and at the output of the device again a high level appears again - the log, 1.

Claims (1)

Claim A telegraph network linear current control device containing a first resistor, the first tap of which is connected to the first input of the device, the second to the eighth resistors, a diode, a zener diode, a transistor, first and second potentiometers, the first taps of which are connected to the second input of the device, and the second tap of the first potentiometer - with the first · device input, an optocoupler including an LED phototransistor pair, the basic input of which is connected through the ninth register to the emitter input, and the collector input is connected through the indicator to a plus a power supply bus, characterized in that, in order to increase the reliability of control, the first and second Schmidt triggers are introduced, the inputs of which are connected respectively through the second and third resistors to the zener diode cathode, which is connected through the fourth resistor to the second input of the device, the inverting inputs of the first and the second Schmidt triggers are connected respectively to the adjustable taps of the first and second potentiometers, and the power inputs are connected respectively to the taps of the fifth and first resistor, the first tap of which ohm is connected to the zener diode anode, and the second tap through the fifth resistor is connected to the second input of the device, the output of the first Schmidt trigger is connected to the second tap of the second potentiometer and through the sixth resistor is connected to the first input of the device, the output of the second Schmidt trigger is connected to the cathodes of the diode ~ \ yes and LED optocoupler, the anode of which is connected through the seventh resistor to the second tap of the first resistor, the key, the first tap of which is connected to the first input of the device, the second tap is connected through the eighth resistor to the second tap of the first resistor, and the control tap is with the diode anode, the tenth resistor, the first tap of which is connected to the emitter input of the phototransistor pair of the optocoupler and the base of the transistor, and the second tap is connected to the emitter of the transistor and the negative bus of the power supply, the eleventh resistor is connected between the positive bus of the power source and the collector of the transistor, which is the output of the device, and the twelfth resistor connected between the anode of the diode and the second tap of the first resistor. Compiled by V. Kurkov Editor E. Kopcha Tehred M. Morgenthal Corrector E. Lonchakova Order 3898 Circulation 517 Subscription VNIIIPI of the State Committee for Inventions and Discoveries under the State Committee for Science and Technology of the USSR 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and Publishing Combine Patent, Uzhgorod, 101 Gagarin St. I