SU1667171A1 - Device for determination of parameters of transient process - Google Patents

Abstract

The invention relates to automation devices and is intended to detect areas in the signal under study with a small steepness of voltage rise, for example, during the movement of the electromagnet rod when it is triggered. The purpose of the invention is to improve the accuracy of determining the parameters. The device consists of a differentiating circuit, a threshold element, two comparators, a voltage divider, by means of which a setpoint voltage is set corresponding to a certain steepness of the input voltage rise. The threshold element eliminates false positives at the time of the end of the transition process. 2 Il.

Description

The invention relates to automation devices and is intended to detect areas in the signal under study with a small steepness of voltage rise, for example, during the movement of the electromagnet rod when it is triggered.

The purpose of the invention is to improve the accuracy of determining the parameters.

Figure 1 shows a diagram of the device; 2 shows timing diagrams for his work.

The device (FIG. 1) contains an input bus 1, a differentiating circuit 2, a threshold element 3, resistors 4 and 5, forming a voltage divider, comparators 6 and 7, an output bus 8.

The threshold element 3. for example, a zener diode connected in parallel to the differentiating circuit 2, the input bus 1 is connected to the forward input of the comparator 6 and the input of the differentiating circuit 2. The voltage divider on the resistors 4 and 5 is connected between the output of the comparator 6 and the common bus of the device. The inverting input of the comparator 6 is also connected to the common bus device. The output of the voltage divider is connected to the direct input of the comparator 7, the inverse output of which is connected to the output of the differentiating circuit 2. The output of the comparator 7 is connected to a common bus. The algorithm of the comparators is such that when the input signals are equal, the output will be low.

The device worked as follows.

At time ti, bus 1 receives the leading edge of the voltage UBx, which further increases with a slope greater than the slope determined by the voltage of the setpoint and set by a voltage divider on resistors 4 and 5 (Fig. 2a). This setting is formed at time t due to the formation at the output of the comparator 6 a positive voltage. The voltage value at the output of the voltage divider is set lower than the voltage at the output of the differentiating circuit 2, therefore, the voltage on the output bus 8 is absent (Fig. 2c). The voltage at the output of the differential circuit is proportional to

with

oh oh

VI

At the time t2, a decrease in the steepness of the voltage UBx occurred, for example, due to the start of movement of the electromagnet core, the voltage at the output of the differentiating circuit 2 decreased, and at the output of the comparator 7 a high voltage level was formed ( Fig.26). At time t3, the steepness of the voltage on the input bus 3 increases again (the electromagnet has stopped measuring), so a low voltage level is formed at the output of the comparator 7 and bus 8. The duration of the output pulse tu formed on bus 8 (fig. 2b) (fig. 2b) is proportional to the section time at the input voltage UBX, where the ramp up is less than the specified one. At time t4, the voltage UBX on the bus 1 exceeded the threshold of the threshold device 3, and a positive voltage is generated at its output, which maintains a low voltage level at the output of the comparator 7.

The need to use the threshold element 3 is due to the fact that in any transition process with time a limitation occurs, at which the rate of increase of voltage gradually decreases to zero. Without the use of a threshold element connected in parallel to the differentiating circuit, a spurious impulse would be formed on the output bus 8, shown in FIG. 2c by a dotted line.

In a number of electromagnets during the movement of the rod, the current through the magnet not only ceases to increase, but also decreases, as shown in Fig. 2a by a dotted line. The device makes it possible to isolate any section with a lower than a predetermined rate of voltage rise, including a negative rate of rise.

Claims (1)

Apparatus for determining transient parameters, comprising a differentiating circuit, a resistor, a comparator, an input and an output bus, characterized in that, in order to improve the accuracy of determining the parameters, a second resistor, a second comparator, a threshold element, and the first and second the resistors are connected in series, the input of the specified threshold element is connected to the input bus, the input of the differentiating circuit and the direct input of the first comparator, and the output of the threshold element is connected to the output The differentiator circuit and the inverting input of the second comparator, the output of the first comparator through these series-connected resistors are connected to the common bus of the device, the inverting input of the first comparator is also connected to the common bus of the device, and the direct input of the second comparator is connected to the connection point of these resistors while the output of the second comparator is connected to the output bus. Yagi i and, Lig 2