JPS6143281A - Electromagnetic pump control circuit - Google Patents

Abstract

PURPOSE:To obtain an electromagnetic-pump control circuit having the superior voltage characteristic by controlling the pulse length of the output pulses supplied from a microcomputer for controlling a one-shot multivibrator and outputting said output pulses. CONSTITUTION:An A/D converter 49 is connected through a constant-voltage element 15. The converted signal is input into a comparator 41. A nonstabilized power voltage is input into the comparator 41 through a resistor 39. Therefore, the digital signal corresponding to the variation of power voltage is outputted from the comparator 41, and input into a microcomputer 16. Said microcomputer 16 controls the length of the pulse and outputs pulses by the above-described signal. The one-shot multivibrator 34 is driven by the output pulses, and a photocoupler 10 is operated. A driving circuit 33 is controlled by the operation of the photocoupler 10, and an electromagnetic pump 5 is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electromagnetic pump control circuit for driving an electromagnetic pump of a combustor.

Conventional technology A conventional electromagnetic pump control circuit is, for example, developed in U.S. Pat.
As shown in Publication No. 847, the pump control circuit and the temperature comparison circuit that controls it receive power from the same commercial power source, and the flow rate of the pump fluctuates greatly in response to fluctuations in the power supply voltage, resulting in poor voltage characteristics. It was something.

The problem that the invention aims to solve The problem is that the voltage characteristics of the electromagnetic pump control circuit are poor.

Means to solve the problem Add a constant voltage power supply to the microcomputer and one-shot multi, input power supply voltage fluctuations to the microcomputer via an A/D converter, input the output to the one-shot multi, and output them. is connected to the electromagnetic pump drive circuit via a hot coupler.

The working microcomputer outputs a pulse with a constant period and constant duty, and adds it to a one-shot multi (monostable multivibrator). Furthermore, if the voltage is high due to power supply voltage fluctuations, the pulse with a long period and the flow rate switching signal are output in one. The output of the one-shot multi is input to a shot multi, and the output of the one-shot multi is applied to a drive circuit that is directly connected to a commercial power supply using a photocoupler to drive an electromagnetic pump.

Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings, and the operation of the second structure.

In the figure, 1 is an AC power supply (commercial power supply), and a diode 2. Resistance 6. The DC power supply circuit of the electromagnetic pump 5 and the isolation transformer 6 are supplied by the capacitor 4 . 63 is a drive circuit for driving the electromagnetic pump 5, which includes resistors 7, 8 . Zener diode9. Transistor 1o- of photocoupler 10
i, a transistor 11°, and a diode 12.

The output of isolation transformer B is a diode bridge 16. It is rectified and smoothed by a capacitor 14, and becomes a constant voltage power source by a constant voltage element 15. 16 is a microcomputer that outputs pulses from an output port 17 and outputs a high level or low level output from an output port 18 depending on the load requirements. Furthermore, resistance 19 to 26. transistor 27.28
゜Variable resistance 29.30. Comparator 61. Light emitting diode 10-2 of photocoupler 1o. A capacitor 32 constitutes a multi-purpose capacitor 34. Drive circuit 6. Since the one-shot multi 64 has a known circuit configuration, detailed description thereof will be omitted. The microcomputer 16 is equipped with an A/D converter 49 that reads power supply voltage fluctuations in order to widen the period of pulses output from the output port 17 when the power supply voltage is high, and to reduce it when the power supply voltage is low. 46.47
．． Resistance 48.35.37, 38.39.40. Comparator 41. Resistance 42. Out capo) 43.44. It is configured by an input port 45. These configurations are conventionally known. Note that the resistor 39 is connected to an unregulated power source.

By outputting increments from output ports 4 and 44 of the microcomputer, the digital value of the power supply voltage can be read depending on whether the output of the comparator 41 is at a high level or a low level. When this digitized power supply voltage is high, a pulse with a large period is output from the output port 17. If it is low, a small pulse is output from the output port 17. When this pulse is output from the high-resolution output port 17,
Transistor 27 turns on, capacitor 32 discharges,
Since the input of the comparator 31 becomes lower than the e input, the output of the comparator 31 becomes low level. Therefore, the light emitting diode 10-2 emits light. Next, when the output report 17 outputs a low level output, the capacitor 32 is charged via the resistor 21. Comparator 31
comparator 6 until the ■ input of becomes higher than the e input.
The output of 1 is low level.

The light emitting diode 10-2 is emitting light. As time passes and the comparator 1 input becomes higher than the e input, the output of the comparator 61 becomes high level and the light emitting diode 1o-2 turns off. Next, the cycle of outputting a high level signal from the output report 17 of the microcomputer 16 is repeated. That is, the one-shot multi-filter 4 outputs a pulse that is delayed by a certain period of time than the pulse output from the microcomputer 17. When the commercial power supply voltage increases, the output of the diode bridge 13 becomes higher, and since the A/D converter 49 via the resistor filter 9 can detect that the power supply voltage has become higher, the microcomputer 16 outputs an output with a wide period. Output from port 17. As the commercial power supply voltage increases, the output of the multi-shot multi 64 becomes an output with a thicker cycle. In the opposite case, the opposite is true.

Further, the pulse width of the output of the one-shot multi 34 (the time during which the light emitting diode emits light) can be achieved by changing the input voltage (reference voltage) of the comparator 31. When a low level output is output from the output port 18 of the microcomputer 16, the transistor 28 is turned off.

The e input voltage of the comparator 31 becomes higher, the time amplification time of the capacitor 31 becomes longer, and the output pulse width of the one-shot multiple becomes longer. If a high level output is output from the output port 18 of the microcomputer 16, the transistor 28
is turned on, the e input voltage of comparator filter 1 becomes low,
The time amplifier time of capacitor 2 becomes shorter, and the output power width of the one-on-one multi-function becomes shorter.

4. Wanyonoto multirole with the above operations. Microcomputer 16. Combine the drive circuit 3 of the electromagnetic pump 5. When a pulse is output from the output port 17 of the microcomputer 16 and a high level output is output from the output port 18 in response to a load request, the transistor 28 is turned on, so the time-up h
r=+u becomes shorter, the output pulse width of the multi-shot circuit becomes shorter, the phototransistor 10-1 is turned on, and the transistor 11 is also turned on. Therefore, electromagnetic pump 5
Since voltage is applied to .

The electromagnetic pump 5 supplies a small flow rate. Here, when the commercial power supply voltage becomes lower, the period of the pulse outputted from the output port 17 of the microcomputer 16 becomes smaller, l'i/J. Therefore, the period of the one-shot multi output pulse becomes smaller.

Therefore, the waveform applied to the electromagnetic pump 5 is a voltage with a small period, but the voltage is low. Conversely, as the AC power supply voltage increases, the period becomes larger and the voltage becomes higher.

Therefore, even if the voltage fluctuates, the electromagnetic pump 5 supplies a constant flow rate. When a low-level output is output from the output port due to a load request, the transistor 28 is turned off, so the time amplifier time becomes longer, the one-shot multi output becomes longer, and the pulse width of the voltage applied to the electromagnetic pump 5 becomes longer. Flow the eave ceiling flow.

Note that the waveform output from the output port 17 of the microcomputer 16 is made using a constant clock of the microcomputer 16.

By counting the frequency of the commercial power supply, pulses with a constant period can be output even if the temperature fluctuates. In other words, since the commercial power supply is fed back, the electromagnetic pump 5 maintains a constant flow rate even if the voltage fluctuates.

As described above, the present invention uses a microcomputer and an A/D converter to read the power supply voltage, and when the power supply voltage is high, applies a pulse with a large period and a load request signal to the one-shot multi-channel signal, and outputs it through a photocoupler. , since it operates the electromagnetic pump drive circuit.

Integrated circuits can be used as circuit configurations.

This has the advantage of improving voltage characteristics.

[Brief explanation of drawings]

The figure is an electrical wiring diagram of an electromagnetic pump control circuit showing one embodiment of the present invention. 5...Electromagnetic pump, 1D...Photocoupler. 16...Microcomputer, 34...Oneshonotoma/l/f
. 49...A/D converter.

Claims (1)

[Claims] A constant cycle from the microcomputer (16) that supplies constant voltage power,
Outputs a pulse with a constant duty and a pulse according to the load request, inputs them to the one-shot multi (34),
In addition, the unregulated voltage is input to the microcomputer (16) via the A/D converter (49), and when the power supply voltage is high, it outputs long-cycle pulses and flow rate switching, and converts them into one-shot multi-channel (34) and their outputs are connected to a drive circuit (33) of an electromagnetic pump (5) via a hot coupler (10).