CN103197112A - An intelligent digital multimeter - Google Patents

Abstract

The application discloses intelligence digital multimeter includes: a front-stage analog signal acquisition circuit for acquiring a front-stage analog signal; is connected with the front section analog signal acquisition circuit through I²The C bus is connected with the microcontroller which controls the front section analog signal acquisition circuit to acquire; and the OLED driving circuit is connected with the microcontroller, receives a control instruction of the microcontroller and drives the organic light-emitting diode OLED. According to the intelligent digital multimeter provided by the invention, the OLED is adopted for displaying, and on the basis of solving the technical defects existing in the existing LCD display, the cost of the multimeter adopting the OLED for displaying is reduced through the design of the internal circuit of the multimeter.

Description

An intelligent digital multimeter

technical field

The invention relates to the technical field of electrical measurement and instruments, and more specifically relates to an intelligent digital multimeter.

Background technique

The multimeter is a multi-functional, multi-range and portable test instrument. The general multimeter can measure DC current and voltage, AC current and voltage, resistance and capacitance, inductance, temperature, crystal transistor amplification factor, diode, etc. A must-have tool for people.

At present, multimeters are divided into analog and digital. The most commonly used digital multimeter is the mainstream of which is to use LCD for display. However, due to reasons such as the LCD process structure and manufacturing process, the existing digital multimeters have the following disadvantages: 1. Since the LCD itself cannot emit light, it is necessary to increase the backlight to adjust the brightness. Although the brightness has been increased by various methods, most of the brightness Uneven; 2. The viewing angle of the LCD is not wide enough. When viewing the LCD from a certain larger angle, the original color cannot be seen, or even all white or all black can be seen; 3. The contrast of the LCD is not wide enough. It is enough for the contrast ratio to reach 350:1, but the professional field cannot meet the needs of users; 4. The response time of LCD is relatively long, generally between 20 and 30ms, and there is a feeling of tail shadow dragging when displaying dynamic images; 5. The digital multimeter display mainly uses the segment code driving method, which makes the multimeter display less information; 6. Because it is a liquid structure, its shock resistance is very poor, and the low temperature cannot be displayed normally at minus 40 degrees. And if OLED (Organic Light Emitting Diode, organic light-emitting diode) is used as the display of the digital multimeter, due to some characteristics of OLED, it will completely solve the above-mentioned shortcomings of the digital multimeter using LCD display. However, in the existing multimeter In technology, because the use of OLED will increase the cost of the multimeter, it is not allowed to use OLED instead of LCD without permission.

Therefore, providing an intelligent digital multimeter, using OLED for display, and reducing the cost of the digital multimeter on the basis of overcoming the shortcomings of the prior art, is a technical problem to be solved urgently by those skilled in the art.

Contents of the invention

In view of this, the present invention provides an intelligent digital multimeter, which uses OLED for display. On the basis of solving the shortcomings of the existing LCD display, it overcomes the problem of increasing the cost of the multimeter in the prior art due to the use of OLED display.

To achieve the above object, the present invention provides the following technical solutions:

An intelligent digital multimeter, comprising:

A front-end analog signal acquisition circuit for collecting front-end analog signals;

A microcontroller that is connected to the front-end analog signal acquisition circuit through an I ² C bus and controls the front-end analog signal acquisition circuit to collect;

The OLED driving circuit is connected with the microcontroller, receives the control instructions of the microcontroller, and drives the organic light emitting diode OLED.

Wherein, the front-stage analog signal acquisition circuit includes:

An analog-to-digital conversion sampling circuit that collects the analog signal of the front-end simulation and converts the analog signal into a digital signal;

An analog signal channel circuit that is connected to the analog-to-digital conversion sampling circuit and collects analog signals such as AC and DC current voltage, resistance, frequency, duty cycle, capacitance, temperature, diode and circuit on-off;

A reference voltage source circuit that is connected with the analog-to-digital conversion sampling circuit and provides a precision reference voltage source for the front-stage analog signal acquisition circuit.

Wherein, the analog signal channel circuit includes: a voltage measurement channel, a current measurement channel, a resistance measurement channel, a capacitance measurement channel, a frequency measurement channel, a diode detection channel and a circuit on-off detection channel respectively connected to the analog-to-digital conversion sampling circuit .

Wherein, the microcontroller is a Cotex M3/M4 microcontroller, and the peripheral is connected with the analog-to-digital conversion sampling circuit, knob scanning circuit, keyboard scanning circuit, clock RTC, EEPROM, PC communication circuit and OLED driving circuit through a general digital interface connected.

Wherein, the microcontroller is respectively connected to the clock RTC and the EEPROM through an I ² C bus.

Wherein, the microcontroller is respectively connected to the knob scanning circuit and the keyboard scanning circuit through a general-purpose input/output port.

Wherein, the microcontroller is connected to the PC communication circuit through a universal asynchronous transceiver port.

Wherein, the drive controller in the OLED drive circuit is an SSD1305 chip, which is connected to the microcontroller through 8-bit parallel port data lines and 5 control lines.

Wherein, the SSD1305 chip is connected to the OLED through 64 COM ports and 128 SEG ports.

It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses an intelligent digital multimeter, which includes: ^a front-end analog signal acquisition circuit for collecting front-end analog signals; A microcontroller connected to the bus to control the acquisition of the front-stage analog signal acquisition circuit; an OLED drive circuit connected to the microcontroller to receive control instructions from the microcontroller and drive the organic light-emitting diode OLED. The intelligent digital multimeter provided by the invention uses OLED for display, and on the basis of solving the technical shortcomings of existing LCD displays, the cost of the multimeter using OLED display is reduced through the design of the internal circuit of the multimeter.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings on the premise of not paying creative efforts.

Fig. 1 is the structural representation of a kind of intelligent digital multimeter disclosed by the embodiment of the present invention;

Fig. 2 is a schematic structural view of the front section analog signal acquisition circuit in a kind of intelligent digital multimeter disclosed by the embodiment of the present invention;

3 is a schematic structural diagram of an OLED drive circuit in a smart digital multimeter disclosed in an embodiment of the present invention;

Fig. 4 is a schematic structural diagram of an intelligent digital multimeter disclosed in an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

An intelligent digital multimeter disclosed by the present invention includes: a front-stage analog signal acquisition circuit for collecting front-stage analog signals; and a circuit connected to the front-stage analog signal acquisition circuit through an I ² C bus to control the front-stage analog signal acquisition circuit to collect A microcontroller; an OLED drive circuit connected to the microcontroller, receiving control instructions from the microcontroller, and driving the organic light emitting diode OLED. The intelligent digital multimeter provided by the invention uses OLED for display, and on the basis of solving the technical shortcomings of the existing LCD display, the cost of the multimeter using OLED display is reduced through the design of the internal circuit of the multimeter.

Please refer to accompanying drawing 1, which is a schematic structural diagram of an intelligent digital multimeter disclosed by an embodiment of the present invention. The invention discloses an intelligent digital multimeter. The specific structure is shown in FIG. The microcontroller 102 is connected to the I ² C bus and controls the front-stage analog signal acquisition circuit to collect; the OLED drive circuit 103 is connected to the microcontroller 102 to receive control instructions from the microcontroller 102 and to drive the organic light-emitting diode OLED.

The intelligent digital multimeter provided by the present invention uses OLED for display. On the basis of solving the technical shortcomings of the existing LCD display, the cost of the multimeter using OLED display is reduced through the design of the internal circuit of the multimeter.

The smart multimeter with OLED display has the following advantages:

1. Because OLED itself can emit light, the brightness can be adjusted by software to make the brightness more uniform;

2. No need to consider the problem of viewing angle, even if you watch it under a large viewing angle, it will still not be distorted;

3. The contrast ratio is also very wide, which can reach 2000:1;

4. The response time is one-thousandth of that of LCD, so there will be no smear phenomenon when displaying dynamic images;

5. OLED adopts dot matrix pixel driving method, which makes the displayed information more;

6. Wide working temperature range, low temperature can also be displayed normally at minus 40 degrees;

7. Because OLED is a solid-state mechanism without liquid substances, its shock resistance is relatively good, and it is not afraid of falling.

Specifically, please refer to FIG. 2 , which is a schematic structural diagram of a front-stage analog signal acquisition circuit in an intelligent digital multimeter disclosed by an embodiment of the present invention. Wherein, the front-stage analog signal acquisition circuit 101 includes: collects the analog signal of the front-stage analog, and converts the analog signal into an analog-to-digital conversion sampling circuit 201 of a digital signal; An analog signal channel circuit 202 for analog signals such as DC current voltage, resistance, frequency, duty cycle, capacitance, temperature, diode and circuit on-off; connected to the analog-to-digital conversion sampling circuit 201, which is the front-stage analog signal acquisition circuit 101 provides a reference voltage source circuit 203 for a precision reference voltage source.

Wherein, the analog signal channel circuit 202 includes: a voltage measurement channel, a current measurement channel, a resistance measurement channel, a capacitance measurement channel, a frequency measurement channel, a diode detection channel, and a circuit on-off circuit respectively connected to the analog-to-digital conversion sampling circuit 201. detection channel. Through the analog signal channel circuit, parameters such as AC and DC voltage and current, resistance, frequency, duty ratio, capacitance, temperature, diode, circuit on-off and low-pass filtering can be measured.

Specifically, please refer to FIG. 3 , which is a schematic structural diagram of an OLED driving circuit in an intelligent digital multimeter disclosed by an embodiment of the present invention. The drive controller in the OLED drive circuit is an SSD1305 chip, which is connected to the microcontroller through 8-bit parallel port data lines (D0-D7) and 5 control lines (RD, WR, D/C, RES, CS); The SSD1305 chip is connected to the OLED through 64 COM ports and 128 SEG ports.

Specifically, please refer to FIG. 4 , which is a schematic structural diagram of an intelligent digital multimeter disclosed in an embodiment of the present invention. Wherein, the present invention adopts embedded system technology, the microcontroller 102 is a Cotex M3/M4 microcontroller, and the periphery communicates with the analog-to-digital conversion sampling circuit, knob scanning circuit, keyboard scanning circuit, clock RTC, EEPROM, PC communication circuit and OLED drive circuit are connected. The microcontroller is connected to the clock RTC and the EEPROM through an I ² C bus; the microcontroller is connected to the knob scanning circuit and the keyboard scanning circuit through a general-purpose input/output port; The microcontroller is connected with the PC communication circuit through a universal asynchronous transceiver port.

In summary: an intelligent digital multimeter disclosed by the present invention includes: a front-end analog signal acquisition circuit for collecting front-end analog signals; connected to the front-end analog signal acquisition circuit through an ^I2C bus, and controls the front-end analog signal A microcontroller for collecting by the acquisition circuit; an OLED drive circuit connected to the microcontroller, receiving control instructions from the microcontroller, and driving the organic light-emitting diode OLED. The intelligent digital multimeter provided by the invention uses OLED for display, and on the basis of solving the technical shortcomings of the existing LCD display, the cost of the multimeter using OLED display is reduced through the design of the internal circuit of the multimeter.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. An intelligent digital multimeter is characterized in that, comprising: A front-end analog signal acquisition circuit for collecting front-end analog signals; A microcontroller that is connected to the front-end analog signal acquisition circuit through an I ² C bus and controls the front-end analog signal acquisition circuit to collect; The OLED driving circuit is connected with the microcontroller, receives the control instructions of the microcontroller, and drives the organic light emitting diode OLED. 2. intelligent digital multimeter according to claim 1, is characterized in that, described front section analog signal acquisition circuit comprises: An analog-to-digital conversion sampling circuit that collects the analog signal of the front-end simulation and converts the analog signal into a digital signal; An analog signal channel circuit that is connected to the analog-to-digital conversion sampling circuit and collects analog signals such as AC and DC current voltage, resistance, frequency, duty cycle, capacitance, temperature, diode and circuit on-off; A reference voltage source circuit that is connected with the analog-to-digital conversion sampling circuit and provides a precision reference voltage source for the front-stage analog signal acquisition circuit. 3. The intelligent digital multimeter according to claim 2, wherein the analog signal channel circuit comprises: a voltage measurement channel, a current measurement channel, a resistance measurement channel, a capacitance Measurement channel, frequency measurement channel, diode detection channel and circuit continuity detection channel. 4. intelligent digital multimeter according to claim 1, is characterized in that, described microcontroller is Cotex M3/M4 microcontroller, and the periphery passes through universal digital interface and described analog-to-digital conversion sampling circuit, knob scanning circuit, The keyboard scanning circuit, clock RTC, EEPROM, PC communication circuit and OLED driving circuit are connected. 5 . The intelligent digital multimeter according to claim 4 , wherein the microcontroller is connected to the clock RTC and the EEPROM respectively through an I ² C bus. 6 . The intelligent digital multimeter according to claim 4 , wherein the microcontroller is connected to the knob scanning circuit and the keyboard scanning circuit through a general input/output port. 7 . 7. The intelligent digital multimeter according to claim 4, wherein the microcontroller is connected to the PC communication circuit through a universal asynchronous transceiver port. 8. The intelligent digital multimeter according to claim 1, wherein the drive controller in the OLED drive circuit is an SSD1305 chip, which is connected to the microcontroller through 8 parallel port data lines and 5 control lines. 9. The intelligent digital multimeter according to claim 8, wherein the SSD1305 chip is connected to the OLED through 64 COM ports and 128 SEG ports.

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