SU845142A1 - Threshold device - Google Patents

Description

I

The invention relates to devices for automation, dosimetry and radiometry, and is intended to form the deviation signals of monitored parameters from the norm.

Known threshold devices containing a threshold element, the input of which through the separation resistors are connected to the outputs of the sources of the monitored and pulse signals, and the output through the capacitor and the quadrupole is connected to the input 1.

The disadvantage of such devices is the lack of galvanic isolation of the input and output circuits and the inability to memorize the fact that the input level exceeds the threshold level.

The closest technical solution to the invention is a threshold device containing a standby blocking generator with a collector base connection, a capacitor and a diode 2.

The aim of the invention is to enhance the functionality by allowing the fact that the input level of the threshold level is memorized.

To achieve this, a key element, the input element of which is directly connected, is introduced into the threshold device containing the waiting blocking generator with collector base connection, the capacitor and the diode.

- to the first bus of the input signal, through a capacitor - to the second bus of the input signal and to the first output of the starting winding of the waiting blocking generator and through the diode to its output and the second output of the starting winding, while the control input of the key element is connected to the control input thickness signal.

FIG. 1 shows the pore device structural diagram; in fig. 2 is the response characteristic of the pore device, while the curve a is the width of the hysteresis loop at

  curve b - width of the loop hyste1) of the ezis at)

The threshold device contains a standby blocking generator 1 with a collector base connection, the input of which is the triggering winding 2 of a pulse transformer connected by one output to the second bus of input signals 3, and the other to the output of the key element 4, whose control input connected to source 5 input

control signal, while the input of the key element 4 is connected to its output through diode 6, directly to the first bus of input signals 7 and through a capacitor 8 to the second bus of input signals.

The pending blocking generator includes a transistor 9, a resistor 10, and a bias source 11.

The threshold device operates as follows.

In the initial state, the capacitor 8 is charged to the voltage of the source of the monitored (input) signal. When the key element 4 controlled by the source 5 of the pulse signal is closed, a pulse is generated on the starting winding 2 of the pulse transformer of the waiting blocking generator whose amplitude is proportional to the value of the output voltage of the source of the monitored signal. If the amplitude of this pulse exceeds the sensitivity threshold of the standby blocking generator 1, the standby blocking generator 1 is triggered. As a result, a pulse is generated on the starting winding 2, which recharges capacitor 8 through diode 6. The increment of voltage on the capacitor 8A Ug is determined the magnitude of the charging current, the duration of the pulse generated by the waiting blocking generator 1, the capacitance of the capacitor 8 and the frequency of the source 5 of the pulsed control signals. The change in the voltage increment on the capacitor 8 is accomplished by changing the pulse duration of the standby blocking generator 1 with a variable resistor 10. The standby blocking generator 1 stops responding to the monitored signal when the pulse amplitude on the triggering winding 2 closes the key element 4 less than the threshold of sensitivity of the waiting blocking generator 1.

If the magnitude of the voltage increment on the capacitor 8 due to the operation of the standby blocking generator 1 is less than the threshold of sensitivity of the standby blocking generator 1, then the response characteristic of the threshold device

has the form shown in FIG. 2, curve a, where UoTn is the release voltage of the waiting blocking generator 1. If the magnitude of the voltage increment on the capacitor 8 D ihhg is greater than the sensitivity threshold of the waiting blocking generator 1 Unop, then the work of the waiting blocking generator G does not stop when the monitored signal to zero values (Fig. 2, curve b), i.e., it is possible to memorize the fact of exceeding the threshold

the level of the monitored signal even when it is disconnected from the input of the threshold device.

Thus, the proposed device has significantly expanded the functionality of the devices by providing a wide range of adjustment of the hysteresis loop width, which allows the fact that the threshold level is exceeded after reducing the value of the monitored signal to zero or

disconnection, as well as by galvanic isolation of the input and output circuits.

Claims (2)

1. USSR author's certificate number 535729, cl. H 03 K 5/20, 15.11.76. 2. USSR author's certificate No. 193185, cl. G 01 R 23/02, 11.10.63 (prototype).