Digital display meter head

Abstract

The utility model provides a digital display gauge outfit which comprises a nixie tube, a first interface and a second interface, the first interface and the second interface are used for being connected with a sensor, a Seg port of the nixie tube is electrically connected with an output end of a driver, a signal input end of the driver is electrically connected with a signal output end of a single chip microcomputer, and a control end of the single chip microcomputer is electrically connected with a COM port of the nixie tube. The single chip microcomputer is electrically connected with the first interface after passing through the differential AD acquisition chip and the amplifier, the first interface is connected with the positive electrode level end of the power supply chip after sequentially passing through the resistor R2, the resistor R3 and the resistor R4, and the common end of the resistor R3 and the common end of the resistor R4 are electrically connected with the REF port of the power supply chip and the REF port of the differential AD acquisition chip respectively; a control circuit for controlling a nixie tube is formed by a stable power supply chip, an amplifier, a differential AD acquisition chip, a single chip microcomputer and a driver, so that a special chip with higher cost is replaced; the utility model has the advantages of simple structure and low cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to display meter head, concretely relates to a digital display meter head. BACKGROUND

[0002] The range output corresponding to the two-wire sensor is a 4-20mA current signal in the loop, wherein, as shown in the figure, the digital display meter head of the two-wire sensor is connected in series with the transmitter loop, and the corresponding physical quantity value is displayed by measuring the 4-20mA current signal in the loop; at present, the digital display part of the sensor is mainly completed by a special chip, and the special chip mainly displays the voltage through a fixed resistor by collecting the current signal, and the value of the corresponding display of 4-20mA is adjusted by adjusting the reference voltage, the adjustment accuracy of the method is limited by the value of the reference voltage, the adjustment range is small, and the accuracy linearity is limited by the special chip, and the cost of the special chip is high. Figure 1 SUMMARY

[0003] In view of the problems in the prior art, the utility model provides a digital display meter head, which aims to reduce the manufacturing cost of the digital display meter head.

[0004] A digital display meter head, comprising a nixie tube and a first interface and a second interface for connecting with a sensor, a Seg port of the nixie tube is electrically connected with an output end of a driver, a signal input end of the driver is electrically connected with a signal output end of a single-chip microcomputer, a control end of the single-chip microcomputer is electrically connected with a COM port of the nixie tube, a signal input end of the single-chip microcomputer is electrically connected with an output end of a differential AD acquisition chip, an input end of the differential AD acquisition chip is electrically connected with an output end of an amplifier, an input end of the amplifier is electrically connected with the first interface, the first interface is connected with a positive level end of a power supply chip in turn through a resistor R2, a resistor R3 and a resistor R4, the positive level end also provides power supply for a second interface, a power supply end of the amplifier, a power supply end of the differential AD acquisition chip and a power supply end of the driver respectively, a common end of the resistor R2 and the resistor R3 is grounded, and a common end of the resistor R3 and the resistor R4 is electrically connected with a REF port of the power supply chip and a REF port of the differential AD acquisition chip respectively.

[0005] Further, the amplifier comprises an operational amplifier, and the operational amplifier is an input rail-to-rail operational amplifier; a negative input pin of the operational amplifier is electrically connected with the first interface through a resistor R1, a positive input pin of the operational amplifier is grounded, and an output pin of the operational amplifier is connected with an input pin Ain of the differential AD acquisition chip through a resistor R6.

[0006] Further, the differential AD acquisition chip is a 24-bit differential AD acquisition chip.

[0007] ​Further, the power supply chip is TL431 and is used for providing the reference voltage with an error range of less than 0.5% for the amplifier.

[0008] Further, the driver is 74HC595D.

[0009] The utility model discloses the beneficial effect has: through the stable power supply chip, amplifier, differential AD acquisition chip, singlechip and driver constitute the control circuit of control nixie tube, to replace the higher cost special chip, the utility model discloses simple structure and low in cost. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The utility model discloses a sensor digital display meter head and the connection circuit structure of transmitter in the prior art.

[0011] Figure 2 The utility model discloses a sensor digital display meter head and the connection circuit structure of transmitter in the prior art. DETAILED DESCRIPTION

[0012] The utility model will be described in detail in combination with the drawings. The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the utility model, and cannot be interpreted as a limitation on the utility model. The left, middle, right, upper, lower and other directions in the embodiments of the utility model are only relative concepts or are referenced to the normal use state of the product, and should not be considered as a limitation.

[0013] A digital display meter head, such as Figure 1As shown, the first interface J1 and the second interface J2 are connected with the transmitter and the series circuit formed by the 9V-36V DC power supply, and the sensor is connected on the first interface J1 and the second interface J2; when the sensor works, the resistor R2, the resistor R3 and the resistor R4 form a voltage dividing circuit, the current through the resistor R2 (20Ω) is 4mA-20mA, the input end of the amplifier U5 is the voltage analog quantity of the resistor R2, the positive electrode of the input end of the differential AD acquisition chip U2 is the voltage analog quantity of the amplifier output, the negative electrode of the input end of the differential AD acquisition chip U2 is the voltage analog quantity of the common end of the resistor R3 and the resistor R4, the digital quantity AD value output by the differential AD acquisition chip U2 is output, the current value in the voltage dividing circuit is calculated, and the single-chip microcomputer U3 drives the digital tube U6 to display the physical value of the sensor corresponding to the current signal through the driver U4.

[0014] The amplifier U5 includes an operational amplifier, and the operational amplifier is a high-precision input rail-to-rail operational amplifier; the negative input pin of the operational amplifier is connected with the first interface J1 through the resistor R1, the positive input pin of the operational amplifier is grounded, and the output pin of the operational amplifier is connected with the input pin Ain of the differential AD acquisition chip U2 through the resistor R6.

[0015] When working, the first interface J1 and the second interface J2 are connected with the transmitter and the series circuit formed by the 9V-36V DC power supply, and the sensor is connected on the first interface J1 and the second interface J2; when the sensor works, the resistor R2, the resistor R3 and the resistor R4 form a voltage dividing circuit, the current through the resistor R2 (20Ω) is 4mA-20mA, the input end of the amplifier U5 is the voltage analog quantity of the resistor R2, the positive electrode of the input end of the differential AD acquisition chip U2 is the voltage analog quantity of the amplifier output, the negative electrode of the input end of the differential AD acquisition chip U2 is the voltage analog quantity of the common end of the resistor R3 and the resistor R4, the digital quantity AD value output by the differential AD acquisition chip U2 is output, the current value in the voltage dividing circuit is calculated, and the single-chip microcomputer U3 drives the digital tube U6 to display the physical value of the sensor corresponding to the current signal through the driver U4.

[0016] The basic principle, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A digital display watch head comprising a nixie tube and a first interface and a second interface for connection to a sensor, characterized in that: The Seg port of the nixie tube is electrically connected with the output end of the driver, the signal input end of the driver is electrically connected with the signal output end of the single-chip microcomputer, the control end of the single-chip microcomputer is electrically connected with the COM port of the nixie tube, the signal input end of the single-chip microcomputer is electrically connected with the output end of the differential AD acquisition chip, the input end of the differential AD acquisition chip is electrically connected with the output end of the amplifier, the input end of the amplifier is electrically connected with the first interface, the first interface is connected with the positive level end of the power supply chip through the resistor R2, the resistor R3 and the resistor R4 in sequence, and the positive level end also provides power supply for the second interface, the power supply end of the amplifier, the power supply end of the differential AD acquisition chip and the power supply end of the driver respectively, the common end of the resistor R2 and the resistor R3 is grounded, and the common end of the resistor R3 and the resistor R4 is electrically connected with the REF port of the power supply chip and the REF port of the differential AD acquisition chip respectively.

2. The digital display watch movement according to claim 1, characterized in that: The amplifier comprises an operational amplifier, and the operational amplifier is an input rail-to-rail operational amplifier; the negative input pin of the operational amplifier is electrically connected with the first interface through the resistor R1, the positive input pin of the operational amplifier is grounded, and the output pin of the operational amplifier is connected with the input pin Ain of the differential AD acquisition chip through the resistor R6.

3. The digital display watch movement according to claim 1, characterized in that: The differential AD acquisition chip is a 24-bit differential AD acquisition chip.

4. The digital display watch movement according to claim 1, wherein: The power supply chip is TL431 and is used for providing a reference voltage with an error range of ≯0.5% for the amplifier.

5. The digital display watch movement according to claim 1, wherein: The driver is 74HC595D.

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