Background
In the measurement and calibration of the sensor, the signal of the sensor needs to be correctly displayed and converted into a measurement engineering unit. The sensors, such as pressure transmitters, tachometers, flowmeters, thermocouples or thermal resistors, output direct current or direct voltage analog signals, which need to be converted into measured values of engineering units such as pressure, rotation speed, flow rate, temperature, etc. during measurement.
The sensor instrument generally comprises a sensor, a transmission line and a display device. The sensor is used for sensing engineering quantity values of the measured environment such as pressure, rotating speed and the like, converting the engineering quantity values into analog signals of direct current voltage or direct current, transmitting the analog signals to the display device through the transmission line, converting and displaying the analog signals by the display device, and simultaneously providing power supply required by the sensor by the display device and transmitting the power supply through the transmission line. The sensors are generally installed at a monitoring site, and output signals of the sensors are transmitted to a display device located in a control room via transmission lines. The transmission line and the display device are generally fixed inside the control room and cannot be detached, so that the measurement and calibration of the sensor are difficult to realize, and the matched display device has a single function, can only be used for displaying signals and engineering units of the matched sensor, and cannot be compatible and universal for other types of sensors. If the signals of a plurality of different types of sensors are acquired, a display instrument for receiving the signals of the sensors is often required to be configured for one type of sensor, the occupied space is large, the equipment is large in size and inconvenient to move, the observation and the recording are troublesome, and the users can easily see the signals wrongly.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the present invention is to provide a display for receiving sensor signals to reduce or avoid the aforementioned problems.
In order to solve the technical problem, the utility model provides a display for receiving sensor signal, the display sets up in a suitcase, the suitcase comprises the drain pan that has the handle and with the top cap of drain pan articulated, one side that the drain pan faced the top cap covers a apron, be formed with an accommodation space between apron and the drain pan, the host computer part of display sets up in the accommodation space, be provided with the LCD that is connected with the host computer part on the apron, power supply interface, switch and be used for connecting the binding post of the signal line of sensor; the liquid crystal display comprises a liquid crystal screen and an input key, wherein the liquid crystal screen and the input key are arranged in parallel to the cover plate.
Preferably, the display instrument comprises an input/output circuit board arranged between the main machine part and the cover plate, and the input/output circuit board is used for transmitting the signals of the sensor received by the wiring terminal to the signal processing module of the main machine part.
Preferably, the display apparatus comprises a power distribution module for supplying power to the input/output circuit board and the host part, and the power distribution module is electrically connected with the power supply interface and the power switch; a power panel is arranged between the power distribution module and the host machine part.
Preferably, the host part comprises the signal processing module, a processor connected with the signal processing module, and a memory, a display controller and a key controller connected with the processor; the display controller and the key controller are respectively connected with the liquid crystal screen and the input keys.
Preferably, the signal processing module includes a signal gating unit, a signal amplifying unit, and an ac-dc converting circuit.
Preferably, the processor is an ARM Cortex-M332 bit RISC processor.
The utility model discloses a display instrument for receiving sensor signal can select to set for different sensor signal sources through the button, and direct current or direct current voltage signal through different sensors convert signal linearity to required measuring engineering unit and show, has improved the measuring commonality of display instrument, has reduced the equipment volume, is convenient for remove the measurement, and measured data brews, the unit is accurate, is convenient for read the difficult mistake that takes place of output.
Detailed Description
In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.
Fig. 1 is a schematic structural view of a display for receiving sensor signals according to an embodiment of the present invention, and as shown in the drawing, the display 100 for receiving sensor signals of the present invention is a suitcase made of aluminum alloy for convenient transportation and carrying, that is, as shown in the drawing, the display 100 of the present invention is disposed in a suitcase, the suitcase is composed of a bottom case 10 having a handle 11 and a top cover 20 hinged to the bottom case 10, a cover 12 covers a side of the bottom case 10 facing the top cover 20, a receiving space is formed between the cover 12 and the bottom case 10, a host portion 30 of the display 100 is disposed in the receiving space, and a liquid crystal display 40 connected to the host portion 30, a power supply interface 50, a power switch 60, and a connection terminal 70 for connecting signal lines of the sensor are disposed on the cover 12; the liquid crystal display 40 includes a liquid crystal panel 41 disposed parallel to the cover 12 and an input key 42.
The utility model provides a display instrument for receiving sensor signal has adopted the structure of the suitcase of a body structure, and the equal complete setting of whole display instrument 100 can carry the transportation with the overall structure lock in the suitcase through top cap 20 inside the suitcase, and compact structure is durable, and adaptability is wide, very makes things convenient for operating personnel to carry it wholly to the scene through handle 11 and connects the measurement to the sensor.
Further, fig. 2 shows a schematic circuit structure diagram of the display apparatus for receiving sensor signals of the present application, and as shown in the figure, the specific structure of the display apparatus 100 shown in fig. 2 of the present application includes an input/output circuit board 13 disposed between the host portion 30 and the cover plate 12, and the input/output circuit board 13 is used for transmitting the sensor signals received by the connection terminals 70 to the signal processing module 31 of the host portion 30.
In addition, the display apparatus 100 further includes a power distribution module 56 for supplying power to the input/output circuit board 13 and the host portion 30, the power distribution module 56 being electrically connected to the power supply interface 50 and the power switch 60; a power strip 57 is provided between the power distribution module 56 and the main body portion 30. In addition, the power distribution module 56 of the present application may also be used to power sensors, may be used to test and calibrate individual sensors, does not require the sensors to be in a live operating state, and reduces the requirements for the test environment.
Further, the host portion 30 includes a signal processing module 31, a processor 32 connected to the signal processing module 31, and a memory 33, a display controller 34, and a key controller 35 connected to the processor 32; the display controller 34 and the key controller 35 are connected to the liquid crystal panel 41 and the input keys 42, respectively.
In addition, the signal processing module 31 includes a signal gating unit 311, a signal amplifying unit 312, and an ac/dc conversion circuit 313 (see fig. 3 for details).
The basic operation principle of the display for receiving sensor signals shown in fig. 2 is that after the display 100 is powered by the power distribution module 56, the voltage or current signals output by the sensors are connected to the display 100 through the connection terminals 70, and the sensor signals are processed by the signal gating unit 311, the signal amplifying unit 312, and the ac-dc conversion circuit 313(a/D conversion circuit). The a/D conversion circuit converts the analog quantity of the signal into a digital quantity for the processor 32(CPU) to perform arithmetic processing. In one embodiment, the processor 32 may be an ARM Cortex-M332 bit RISC processor, and the sensor signals are collected and processed before being sent to the memory 33 for storage. In order to be compatible with the conventional PC, the display device 100 of the present application preferably uses the PC/104 bus technology, the memory 33 can be used to store the solidified program through the ROM, and the RAM can be used to store the historical data processed by the CPU. After power-on, the ROM program enables the CPU to start operating. In addition, the display apparatus 100 of the present invention may further include a human-computer interface, for example, an interface for interfacing with external devices such as a hard disk, a floppy drive, a display, a keyboard, and a mouse.
Fig. 3 shows a schematic diagram of a signal processing circuit of a display for receiving sensor signals according to another embodiment of the present invention, in which the processing of different sensor signals is shown. As shown in the figure, after the sensor signal is input into the display through the connection terminal 70 on the cover plate 12, the sensor signal firstly passes through the signal conditioning circuit 314 of the input/output circuit board 13, and then enters the signal gating unit 311 of the signal processing module 31. The output signals of the different sensors may be voltage, current, thermocouple and thermal resistor, the terminals 70 on the panel 12 are respectively set according to the different types of signals, and different terminals should be connected to the different sensors during operation, and then the buttons 42 are used to select and set in the menu displayed on the display 41, for example, the type of signal, project unit, upper range limit, lower range limit, signal cutoff and other information can be set. After setting, the CPU may select the input signal to be measured by the signal gating unit 311 according to the setting information, for example, select the signal to be further processed by the signal amplifying unit 312 and the ac/dc converting circuit 313, and finally record the measured value.
FIG. 4 shows a current and voltage signal conversion circuit diagram for a display for receiving sensor signals according to the present application. As shown in the figure, since the input signal to the ac/dc conversion circuit 313 must be converted into a voltage signal for measurement, the present application selects to convert the input current signal into a voltage signal in a linear relationship therewith. As shown in the figure, input signals of different specifications are first converted into voltage signals (directly input to the converter 3131 of the ac/dc conversion circuit 313 if the voltage signals are), and then the voltages are output to the measurement part for processing. For example, the input current is first converted into an input voltage ui ═ is ═ R1 by Rl, and then subjected to in-phase input proportional amplification to obtain an output voltage u0 ═ is ═ R1(1+ R2/R3). The load R1 is sized according to the sensor current output requirement. After R1 is determined, R2 and R3 are determined according to the ranges of is and u 0. In order to reduce the error caused by the bias current of the operational amplifier, the ground resistances of the two input ends are required to be equal, i.e. R4 ═ R2R3/(R2+ R3). In one embodiment, the converter 3131 may be an existing 28-pin dual in-line package AD1674 converter, which is a relatively common converter suitable for measuring voltage signals by successive approximation, and comprises a comparator, a D/a converter, an output register, and control logic, and the basic principle is to obtain the lowest voltage measurement value by probing from high to low bits. The principle of measuring the voltage signal by using the successive approximation method of the existing AD1674 converter is the prior art, and the configuration setting can be performed by referring to the product specifications of different manufacturers, and the prior art is not described in detail herein.
Further, fig. 5 shows a schematic circuit diagram of the signal amplifying unit 312 of the present application. That is, when the input signal is a weak voltage signal, the signal u1 needs to be amplified to u2 to better match the range of the ac-dc converter circuit 313, thereby improving measurement accuracy and sensitivity. In a specific embodiment, a programmable amplifier (PGA)3121 may be used to amplify the signal, and the gain of the amplifier is changed according to the magnitude of the analog signal u1 to be measured, so as to implement automatic switching of the measuring range. Gain G is (R5+ R6)/R6, and gain control is realized by adjusting the ratio of feedback resistors R5 and R6 to obtain an amplified signal u 2-u 1G.
To sum up, the utility model discloses a display for receiving sensor signal can select to set for different sensor signal sources through the button, and direct current or direct current voltage signal through different sensors convert signal linearity to required measuring engineering unit and show, has improved the measuring commonality of display, has reduced the equipment volume, is convenient for remove the measurement, and measured data is made, the unit is accurate, is convenient for read the difficult mistake that takes place of output.
It is to be understood by those skilled in the art that while the present invention has been described in terms of several embodiments, it is not intended that each embodiment cover a separate embodiment. The description is given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including all technical equivalents which are encompassed by the claims.
The above description is only exemplary of the present invention, and is not intended to limit the scope of the present invention. Any equivalent changes, modifications and combinations that may be made by those skilled in the art without departing from the spirit and principles of the invention should be considered within the scope of the invention.