JP3139138B2 - Remote time setting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master unit for giving a voltage command corresponding to the magnitude of a time command to a voltage source, and receiving an output of the voltage source having a voltage value of the magnitude of the voltage command through a signal line. The present invention relates to a remote time setting device that includes a slave unit, the slave unit includes a capacitor charged by the output, and a discharge circuit, and includes a voltage detector that generates a time-up signal when the voltage of the capacitor decreases to a predetermined level.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration of a conventional remote time setting device. In FIG. 2, reference numeral 10 denotes a time setting device as a master unit, and reference numeral 20 denotes a time circuit as a slave unit. Master device 10
For example, the arithmetic processing unit CPU 11 and the constant voltage generator 12
When the time command T is generated, the CPU 10 converts the time command T into a voltage command S having a magnitude corresponding to the time command and provides the voltage command S to the constant voltage generator 12. The constant voltage generator 12 outputs a voltage Vs having a magnitude specified by the voltage command S, and the voltage Vs is sent to the time limit circuit 20 through the wiring 30. The timing circuit 20 has a capacitor 21, which is charged to the voltage Vs by the output of the time setting device 10. Thereafter, the capacitor 21 is discharged through a discharge circuit (not shown), but the reference voltage value (time detection voltage) _Vr
When the voltage is discharged until the voltage becomes, the voltage detection circuit 22 detects this and outputs it. The time T from when the capacitor 21 starts discharging until the voltage detection circuit 22 generates a detection signal (time-up signal) is a set time limit.

T = −τ × LnV _r / V _S (1) where τ = capacity of capacitor 21 and impedance of the discharge circuit Discharge time constant determined by

[0004]

As is apparent from the above equation (1), the accuracy of the set time period T depends on the accuracy of the voltage V _S , the reference voltage value (time detection voltage) _Vr, and the discharge time constant τ. You. Of these time-related parameters, the accuracy of the discharge time constant τ greatly varies depending on individual elements and ambient temperature conditions. As shown in FIG. 3, the discharge time constant τ is τ ₁ ,
The variation and the set time period T are shifted like T ₁ and T ₂ like τ ₂ .

The present invention has been made to solve this problem, and it is an object of the present invention to provide a remote time setting device capable of improving accuracy as compared with the prior art.

[0006]

To achieve the above object, according to the present invention, there is provided a master unit for providing a voltage command corresponding to the magnitude of a timed command to a voltage source; A slave unit that receives an output having a voltage value of a magnitude through a signal line; the slave unit includes a capacitor and a discharge circuit that are charged by the output; In the remote time setting device including a generated voltage detection circuit, the master unit checks the value of the time-related parameter of the slave unit,
The magnitude of the voltage command is determined with reference to this value.

In the present invention, when determining the magnitude of the voltage command, the master unit detects the voltage of the capacitor, calculates the capacitance of the capacitor from the voltage, and refers to the calculated capacitance of the capacitor. did.

[0008]

According to the present invention, when the voltage command is generated and the time is set, the current value of the time-related parameter of the element of the slave unit is checked to determine the magnitude of the voltage command. Even if the values of these parameters fluctuate, accurate time limit settings can always be obtained.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 13 denotes a voltage detection circuit for detecting the voltage Vc of the capacitor 21.
When receiving the timing setting command T, the voltage V _M for sensing outputs a command M to the constant voltage generator 12 generates a (<V _S), reads the voltage Vc after the set time T _S, the following equation The capacity C of the capacitor 21 is calculated.

[0011] Here, R _imp is the impedance of the discharge circuit. The CPU 11 determines the magnitude of the voltage command S with reference to C.

The subsequent operation is the same as in the prior art.

[0013]

As described above, according to the present invention, when the voltage command is generated to set the time limit, the current value of the time-related parameter of the element of the slave unit is checked to determine the magnitude of the voltage command. Even if the values of these parameters fluctuate due to fluctuations in the ambient temperature or the like, accurate time limit settings can always be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional remote time setting device.

FIG. 3 is a characteristic diagram for explaining a problem of the conventional example.

[Explanation of symbols]

 Reference Signs List 10 master unit 11 CPU, 12 constant voltage generator 13 voltage detection circuit 20 slave unit 21 capacitor 22 voltage detection circuit

Claims (2)

(57) [Claims] 1. A master unit for giving a voltage command corresponding to the magnitude of a timed command to a voltage source, and a slave unit for receiving, via a signal line, an output of the voltage source having a voltage value of the magnitude of the voltage command, In a remote time setting device having a capacitor which is charged by the output and a discharge circuit, and a voltage detection circuit which generates a time-up signal when the voltage of the capacitor decreases to a predetermined level, the master unit includes: A remote time setting apparatus characterized in that the value of a time-related parameter of a slave unit is checked, and the value of the voltage command is determined with reference to the value. 2. When determining the magnitude of the voltage command, the master unit detects the voltage of the capacitor, calculates the capacitance of the capacitor from the voltage, and refers to the calculated capacitance of the capacitor. The remote time setting device according to claim 1.