JPS61173308A - Parameter setting device - Google Patents

Abstract

PURPOSE:To set parameter with simple hardware by detecting the value of a variable resistance as a time corresponding to the time constant of a time constant circuit, and obtaining the parameter value from the detected time and the content of memory that stores a parameter value of each time. CONSTITUTION:A resistance value R of a variable resistance 1a corresponds uniquely to the time constant (r) of a time constant circuit 1, and a time measuring circuit 2 measures time T corresponding to the time constant (r). Accordingly, the time T corresponds uniquely to the resistance value R of the variable resistance 1a. Parameter values corresponding to each value of the time T are stored beforehand in a storage circuit 3 and consequently, the resistance value R of the resistance 1a corresponds uniquely to the parameter value. Thus, for instance, parameter values corresponding to resistance values are graduated on the knob of the resistance 1a. When the resistance value of the resistance 1a is changed to a resistance value corresponding to a parameter value to be set, and time T corresponding to the time constant (r) of the circuit 1 is measured by the circuit 2, the parameter value stored in the circuit 3 is searched from the time T, and the parameter value is set.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for setting parameters in a microcomputer, and in particular to a device for measuring the amount of change in the resistance value of a variable resistor as the amount of change in the charging time constant or the discharging time constant. According to
The present invention relates to a parameter setting device that can set parameters in a microcomputer with less hardware and a smaller number of ports.

BACKGROUND ART Conventionally, when setting parameters that can be changed as appropriate in a microcomputer of a microcomputer-applied device, the terminal voltage of a variable resistor for parameter value input is converted into a digital quantity by an A/D converter, or by converting a plurality of Generally, a method is adopted in which coded parameter values are generated using a digital switch for inputting parameters, and the values are input into a microcomputer through a plurality of input ports.

Problems to be Solved by the Invention However, in such a system, external hardware becomes complicated, such as an A/D converter, and a microcomputer with a large number of input ports is required, resulting in high costs.

The present invention solves these conventional problems, and its purpose is to provide a parameter setting device that can set parameters in a microcomputer using less hardware and fewer ports.

Means for Solving the Problems In order to solve the above problems, the present invention, as shown in FIG. A time measuring means 2 that measures time according to a constant, a storage means 3 that stores parameter values corresponding to each time measured by the time measuring means 2, and parameters corresponding to the times measured by the time measuring means 2. and a parameter determining means 4 for reading values from a memory 13. In a preferred embodiment of the present invention, the time measuring means 2 measures the time required from the time when a voltage at a predetermined level is applied to the input of the time constant circuit 1 until the output voltage rises to a predetermined level. In other embodiments,
The time measuring means 2 measures the time required from the time when the application of the voltage at the predetermined level applied to the time constant circuit 1 is stopped until the output voltage decreases to the predetermined level.

Since the resistance value R of the variable action resistor 1a and the time constant τ of the time constant circuit 1 uniquely correspond to each other, and the time measuring means 2 measures a time T corresponding to the time constant τ, this time T is also It uniquely corresponds to the resistance value R of the variable resistor 1a. In addition, storage means 3
Since parameter values corresponding to each value of time T are stored in advance in , the resistance value R of the variable resistor 1a and the parameter values etc. correspond uniquely after all. From the above relationship, for example, the knob of the variable resistor 1a is graduated with a parameter value corresponding to the resistance value, and the resistance value of the variable resistor 1a is switched to the resistance value corresponding to the parameter value to be set, and the time counting means 2 When the time T corresponding to the time constant τ of the time constant circuit 1 is measured, the parameter value stored in the storage means 3 is searched from the time T, and the parameter value is set.

Example FIG. 2 is a block diagram of main parts of an embodiment of the present invention.

In the figure, 10 is a so-called one-chip microcomputer having an internal ROM, RAM, etc., and operates in synchronization with a clock frequency defined by an externally attached oscillator 11. Power supply terminal Vcc of microcomputer 10
For example, a DC voltage of +5V is applied to the earth terminal V
SS is grounded. Also, one output port (OUT) of the plurality of output ports is connected to +5V via a resistor R, and is also connected to the input of a time constant circuit 12 consisting of a series circuit of a variable resistor R and a capacitor C. The output of the zero time constant circuit 12, that is, the voltage at the connection point between the variable resistor R and the capacitor C, is input to the ten terminal of the comparator 13 and compared with the reference voltage vth applied to one terminal. The output of this comparator 12 is connected to one input port IN of the plurality of input ports of the microcomputer 10. It should be noted that various other input signals are input to the microcomputer 10, and various signals for control are outputted, but these are not shown.

As shown in FIG. 3, when the output port OUT of the microcomputer 10 is at a low level (hereinafter referred to as "Ll"), the terminal voltage of the capacitor C is approximately zero.The potential of the output port OUT is set to a high level at time t1. (Hereinafter “H
”), a voltage Vo at a predetermined level is applied to the input of the time constant circuit 12, and the terminal voltage V of the capacitor C is
changes according to the following equation.

yxvo
”.Output port 0 [The time when IT was set to “H” is -
The time T from t2 to time t2 when the output of the comparator 13 becomes H'' is a time corresponding to the time constant of the time constant circuit 12, and changes as the value of the variable resistor R is changed.Vth, R, T
The relationship is shown in the following equation.

Figure 4 shows capacitor C in Figure 2 as 10IIF, resistor R,
This is an actual measurement value showing the relationship between the resistance value of the variable resistor R and the time T when V is set to 10Ω and the reference voltage vth is set to 1V. As shown in Figure 4, if the value of the variable resistor R is changed from 39Ω to 120Ω, the time T will be 190m s.
It can be varied from 580m5 to 580m5.

When using the range of time T from 190ms to 580ms, the internal RO of the microcomputer 1o
For example, as shown in FIG.
1 second for 90m5, 2 seconds for 200m5,
When the distance is 580 m5, the parameter value is set as 40 seconds.

In addition, on the knob of the variable resistor R, for example, as shown in the plan view of Fig. 6, there is a 1 second scale at the Ω position for resistance value 39, a 40 second scale at the Ω position for resistance value 120, and a 40 second scale at the Ω position for resistance value 39. are graduated with parameter values corresponding to each resistance value.

Next, the operation of this embodiment will be explained. For example, if you want to set 1 second as a parameter value, set the knob of variable resistor R to the 1 second scale. The level of the output port OUT before the power is turned on is "L", and the voltage of the capacitor C is approximately zero. When the power is turned on, the microcomputer 10 executes processing as shown in FIG. That is, first, the output port OUT is changed from "L" to "H" (S1), and from that time the internal counter CNT is counted up until the voltage at the input port IN becomes "H" (S2, S3). When the output port becomes "H", capacitor C is charged via resistors R, R,
When the terminal voltage reaches the reference voltage vth, the comparator 1
3 becomes "H" and the input port IN becomes "H", the microcomputer 10 stops counting the counter CNT, moves to step S4, and outputs the output port OU.
The capacitor C is discharged by changing T from "H" to "L".Then, the parameter value corresponding to the value of the counter CNT (which indicates time T) is stored in the internal ROM. Obtain from the correspondence table with values (S5
). This obtained parameter value becomes the parameter value set this time. Note that if the measured time T is not divisible by 10 m5, the parameter value is searched by rounding off to the nearest whole number, or the parameter value is determined by interpolation. After completing such parameter setting processing, the microcomputer 10 performs normal signal processing or execution of a control program (S6).

In the above embodiment, the parameter value is set according to the charging time constant of the time constant circuit 12, but the time constant circuit 12
Of course, it is also possible to use a time corresponding to the discharge time constant of . However, if the discharge time constant is used, it will take extra time to charge the capacitor C once.

As described in detail, in the present invention, a time constant circuit whose time constant can be changed by a variable resistor is provided, and the value of the variable resistor is detected at a time corresponding to the time constant of the time constant circuit. The parameter value to be set is determined from the time and the memory contents that store the parameter value for each time, eliminating the need for an A/D converter and multiple digital switches as in the past, and using simple hardware. There are effects that can be achieved with Furthermore, the time measurement means, storage means, and parameter determination means can be realized inside the microcomputer, and connection with the time constant circuit requires only two signal lines, which has the effect of allowing parameters to be set with a small number of ports.

[Brief explanation of drawings]

Fig. 1 is a configuration explanatory diagram of the present invention, Fig. 2 is a block diagram of main parts of an embodiment of the present invention, Fig. 3 is a timing chart showing an example of signal waveforms of each part in Fig. 2, and Fig. 4 is a variable resistor. A diagram showing the relationship between the resistance value of R and time T, Figure 5 is a diagram showing the correspondence between time T and parameter values, Figure 6 is a plan view of the knob of variable resistor R, and Figure 7 is a diagram showing the relationship between the resistance value of R and time T. is a flowchart showing an example of parameter setting processing of the microcomputer 10. 10 is a microcomputer, 12 is a time constant circuit, 13
is a comparator, R is a variable resistor, C is a capacitor, OUT is an output port, and IN is an input port.

Claims (3)

[Claims] (1) A time constant circuit whose time constant can be changed by a variable resistor, a time measuring means for measuring time according to the time constant of the time constant circuit, and parameters corresponding to each time measured by the time measuring means. A parameter setting device comprising: a storage means for storing a value; and a parameter determination means for reading a parameter value corresponding to a time measured by the time measurement means from the storage means. (2) In the parameter setting device according to claim 1, the time measuring means is configured to measure the time from the time when a voltage at a predetermined level is applied to the input of the time constant circuit until the output voltage rises to a predetermined level. A parameter setting device characterized in that it measures the time required. (3) In the parameter setting device according to claim 1, the time measuring means is arranged such that the output voltage reaches a predetermined level from the time when the application of the voltage at the predetermined level applied to the input of the time constant circuit is stopped. A parameter setting device characterized in that it measures the time required for the parameter to drop to a certain level.