JPH03289394A - Voltage setter - Google Patents

Abstract

PURPOSE:To realize a voltage setter which rapidly detect a malfunction even if the malfunction occurs in a constant-voltage source circuit and obtain stable output characteristic by deciding whether the output side voltage of a variable resistor falls within a predetermined valid range or not. CONSTITUTION:A contact 8 of a switch 7 is closed, a comparator 12 reads an input voltage 1, decides whether it falls within a predetermined valid range or not, and it is added by a calculator 13 if it falls within the range. If it is decided to be out of the range, the number of the input voltages is counted. Whether this value is less than the total number (n) of the input voltages or not is decided, and if it is less than that, the voltage 1 is switched to an input voltage 2 by a switching circuit 15. If both are out of the range, i.e., if the counted value becomes 2, a switching discriminator 14 sends a command to a calculator 13, holds the previous value, and continuously outputs it as a speed command.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a voltage setting device that sets a control target voltage for a speed command using a plurality of endless variable resistors, for example in a speed control device for an electric motor. It is related to.

[Conventional technology]

FIG. 3 is a circuit diagram showing the configuration of a conventional voltage setting device of this kind using a double endless variable resistor. In the figure, (1) and (2) are the outputs of the variable resistor! The input voltage is a voltage, and its generation circuit is shown in FIG. In Figure 4, (3) is a constant voltage source that generates a constant voltage;
) and (The phrases refer to each variable resistor that is a component of a double endless variable resistor, operated by a common rotation axis, and the resistance value of its output terminal becomes zero every time this rotation axis rotates 360 degrees.) The variable resistors (4) and (5) are arranged so that their sliding diameters are offset from each other by 180 degrees.

Returning to Figure 1, (6) is an analog/digital converter,
(7) is a switch consisting of contacts (a and (9), (lO
) is a switching circuit, and (11>) is an addition circuit.

Next, the operation will be explained. First, the characteristics of input voltages (1) and (2) will be explained with reference to FIG. In the figure, the horizontal axis is the rotation angle θ of the rotation axes of the variable resistors (4) and (5). Then, the input voltage (1) is its upper limit value A
and the lower limit B. Similarly,
The input voltage (2) is used between its upper limit value C and its lower limit value. Input voltage (1) and input voltage (2) are generated with a rotation angle θ of 180°.

Here, when the switching circuit (10) turns on the contact (8) and turns off the contact (9) and increases the rotation angle θ from 0°, the input voltage (1) becomes as shown in Fig. 5. , increases linearly. This voltage is converted into a digital value by an analog/digital converter (6) at regular intervals,
A speed command as a set voltage value is output via a contact (8) and an adder circuit (11). When the input voltage (1) reaches the upper limit value A, the switching circuit (lO) operates and the switching device (
7). That is, contact (8) is turned off, contact (9)
Turn on. At the same time, the adder circuit (+1) memorizes the value immediately before switching, and thereafter adds the value of the input voltage (2) input via the contact (9) to the memorized value and continuously outputs the speed command. To go.

[Problem to be solved by the invention]

Since the conventional voltage setting device is configured as described above,
If the output of the constant voltage source (3) stops for some reason or the input line of the variable resistor (4) or variable resistor (5) is disconnected, protective actions will be required in response to this abnormality. There is a problem in that as a result of sudden changes in the speed command, which is the set voltage value to be output, the control system becomes unstable and the above-mentioned protective operation cannot be fully achieved.

This invention was made to solve the above-mentioned problems, and it provides a voltage setting device that can quickly detect any abnormality that occurs in the constant voltage source circuit and that can provide stable output characteristics. The purpose is to realize this.

[Means and effects for solving the problem] The voltage setting device according to the present invention determines whether or not the output side voltage of a variable resistor is within an effective range predetermined for the variable resistor, and If it is within the range, add the output side voltage of the variable resistor above to the output value of the previous set voltage value and output it as the set voltage value, and if it is outside the effective range, remove the variable resistor above. When the output side voltage of all variable resistors goes out of the effective range, the output value of the set voltage value up to that point is maintained.

In this case, when the constant voltage source is cut off, the output side voltages of all the variable resistors are out of the effective range, and the set voltage value remains at the output value up to that point.

〔Example〕

FIG. 1 is a circuit diagram showing the configuration of a voltage setting device according to an embodiment of the present invention.
(9) is the same as the conventional one, and its explanation will be omitted. (+2
) is a comparison circuit that determines whether the input voltage value is within the effective range predetermined by each variable resistor.
When it is within the effective range, an operation command is sent to the arithmetic circuit (13) to perform the same addition operation as the conventional adder circuit (11), and when it is outside the effective range, the switching discrimination circuit (I
4) Sends the operation command. The switching discrimination circuit (14) sends an operation command to the switching circuit (15) to select an input voltage other than the input voltage determined to be outside the valid range, and re-input voltage]1) and (2) are both valid. If it is determined that it is outside the range, an operation command is sent to the arithmetic circuit (13) to hold the immediately previous output value.

Next, the operation will be explained with reference to the flowchart shown in FIG. First, the contact (81) of the switch (7) is turned on and the comparator circuit (12) reads the input voltage (1) (step 2). The comparator circuit (12) determines whether or not this input voltage (1) is within a predetermined effective range (step ■),
If it is within the valid range, the arithmetic circuit (13) performs an addition operation (step 2). This operation is performed using the conventional addition port Fr/1 (
l It is similar to that according to I). When END is reached, the process returns to the step and repeats this flow calculation at a constant cycle.

If step ■ determines that it is outside the valid range, count the number of input voltages determined to be outside the valid range (step ■) (
Here, the count value is -1). Next, it is determined whether or not this count value is less than the total number of input voltages n (n-2 in this example).
5), the input voltage (1) is switched to the input voltage (2) (step ■).

When both the input voltage (1) and the input voltage (2) are out of the effective range, that is, when the count value becomes 2, the determination in step
) to hold the previous value and continue outputting it as a speed command (step ■).

Therefore, if there is no abnormality in the constant voltage source (3) etc., a switching operation similar to that conventionally explained with reference to FIG. 5 will be performed and a continuous speed command output will be obtained. In addition, a constant voltage source (3
) or an intermittent fault occurs in this circuit, it is determined that both input voltages (1) and (2) are outside the effective range, and the operation flow is as shown in step (2) in FIG. Therefore,
The speed command maintains the previous value without sudden changes, and subsequent protective operations are executed without any problems.

In addition, although the above embodiment describes the case where a double variable resistor is used, the present invention is equally applicable to the case where a multiple variable resistor in which more variable resistors are linked together is used. This can produce the same effect.

〔Effect of the invention〕

Since the present invention is configured as described above, even if an abnormality occurs in the circuit of the constant voltage source, this can be quickly detected, sudden changes in the output value can be avoided, and stable operating characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of a voltage setting device according to an embodiment of the present invention, FIG. 2 is a flowchart for explaining its operation, and FIG. 3 is a circuit diagram showing the configuration of a conventional voltage setting device. FIG. 4 is a circuit diagram for generating the input voltage, and FIG. 5 is a diagram showing the characteristics of the input voltage when the rotation angle of the variable resistor is changed. In the figure, (11 (2) is the input voltage as the output side voltage of the variable resistor, (3) is the constant voltage source, (4) (51 is the variable resistor, (12) is the comparison circuit, and (13) is arithmetic circuit,
(14) is a switching determination circuit, and (15) is a switching circuit. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 2

Claims (1)

[Claims] In a device that outputs a continuous set voltage value by sequentially selectively switching each output circuit of a plurality of endless variable resistors connected to a constant voltage source and accumulating the output side voltage of each variable resistor, It is determined whether the output side voltage of the variable resistor is within the effective range predetermined for the variable resistor, and if it is within the effective range, the output value of the previously set voltage value is set to the variable resistor. The output side voltages of the resistors are added and output as the set voltage value, and if it is outside the valid range, it is switched to another variable resistor except the variable resistor above, and the output side voltage of all variable resistors is valid. A voltage setting device characterized in that when the voltage falls outside the range, the output value of the previously set voltage value is held.