An IEEE1451.4 common signal line intelligent sensor automatic test system

Abstract

The present invention provides an automatic test system for an IEEE1451.4 common signal line type intelligent sensor, including a power input interface, a constant current source circuit, a digital-analog port switching circuit, a DCtoDC step-down voltage stabilizing circuit, a main control microprocessor, a human-computer interaction circuit and a sensor interface to be tested; the power input interface inputs a DC power supply to power the constant current source circuit and the DCtoDC step-down voltage stabilizing circuit; the DC power supply is a single power supply for the automatic test system, and the constant current source circuit provides energy for the sensor to be tested of the automatic test system when it works in a simulation state, adopts a reasonable digital-analog switching circuit design, and the test system does not need to adopt negative power supply logic power supply during operation, and can be used normally without negative signal conversion, the circuit design is simple, and the human-computer interaction circuit can ensure that the system can still perform testing work when there is no host computer. The present invention has the advantages of intuitive data output, stable system operation, and simple measurement, thereby filling the gap in the domestic and foreign markets.

Description

[Technical field]

[0001] The invention relates to an automatic sensor testing system, in particular to an IEEE1451.4 common signal line type intelligent sensor automatic testing system. [Background technology]

[0002] With the development of electronic technology and manufacturing technology, the intelligence of sensors is becoming more and more popular, among which IEEE1451.4 common signal line type smart sensors are increasingly used. IEEE1451.4 common signal line type smart sensors generally use a 2-wire interface. The commonality of this type of interface is that the analog and digital functions share a signal line. At present, the smart sensor tests commonly used in the domestic and foreign markets generally use the "IEEE1451.4 data acquisition system", such as Figure 1 As shown in the figure, it is the principle block diagram of the IEEE1451.4 data acquisition system. This type of test system usually needs to adopt negative power supply logic power supply, the circuit design is relatively complex, the data processing is relatively cumbersome, the data acquisition system cost is relatively high, and this type of data acquisition system is generally inseparable from the host computer. [Summary of the invention]

[0003] In view of this, the technical problem to be solved by the present invention is to provide an IEEE1451.4 common signal line type intelligent sensor automatic testing system, which is powered by a single power supply and can be used normally without negative power supply signal conversion for data processing. The circuit design is simple, and the test system integrates buttons and display windows to ensure that the system can still perform testing work without the intervention of a host computer.

[0004] In order to achieve the purpose of the aforementioned invention, the technical solution adopted by the embodiment of the present invention is: an automatic test system for IEEE1451.4 common signal line type intelligent sensor, characterized in that it includes: a power input interface, a constant current source circuit, a digital-analog port switching circuit, a DCtoDC step-down voltage stabilization circuit, a main control microprocessor, a human-computer interaction circuit and a sensor interface under test;

[0005] The power input interface is respectively connected to the constant current source circuit and the DCtoDC step-down voltage stabilizing circuit; the constant current source circuit, the digital-analog port switching circuit and the interface of the sensor under test are connected in sequence; the DCtoDC step-down voltage stabilizing circuit is respectively connected to the digital-analog port switching circuit, the main control microprocessor and the human-computer interaction circuit; the main control microprocessor is also respectively connected to the digital-analog port switching circuit and the human-computer interaction circuit;

[0006] The power input interface inputs a DC power supply to power the constant current source circuit and the DCtoDC step-down voltage stabilization circuit; the DC power supply is a single power supply for the automatic test system;

[0007] The constant current source circuit generates a variable constant current source for the sensor under test to work in the analog function;

[0008] The digital-analog port switching circuit performs a switching function between the analog function execution circuit and the digital function execution circuit during the test process;

[0009] The DCtoDC step-down voltage stabilization circuit converts the DC voltage into the normal operating voltage of the main control microprocessor, the human-computer interaction circuit, and the digital-to-analog port switching circuit respectively;

[0010] The main control microprocessor performs test instruction control and data processing;

[0011] The human-computer interaction circuit provides a human-computer interaction function;

[0012] The sensor interface to be tested is connected to the intelligent sensor to be tested.

[0013] Furthermore, the automatic test system of the present invention further comprises an audible and visual alarm circuit, which is respectively connected to the DCtoDC step-down voltage stabilization circuit and the main control microprocessor, and alarms when an abnormal state occurs during the automatic test process;

[0014] Furthermore, the automatic testing system of the present invention also includes a USB to serial port circuit, which is respectively connected to the DCtoDC step-down and voltage stabilization circuit and the main control microprocessor to download the compiled system software to the main control microprocessor.

[0015] Furthermore, the USB to serial port circuit specifically includes a USB interface, a low-pass filter, a communication conversion chip, a serial port data external interface and a serial port output high level selection circuit;

[0016] Furthermore, the VDDIO pin of the communication conversion chip is connected to the serial port output high level selection circuit, and the TX pin is connected to the serial port data external interface through the diode D5 and the resistor 18 in sequence.

[0017] Furthermore, the USB to serial port circuit specifically includes an anti-static protection circuit and a short-circuit protection circuit, the anti-static protection circuit is connected to the USB interface, and the short-circuit protection circuit is respectively connected to the USB interface, the anti-static protection circuit and the low-pass filter.

[0018] Further, the digital-to-analog port switching circuit specifically includes a double-pole double-throw relay K1, a drive control transistor Q1, an indicator light LED1 and an indicator light LED2;

[0019] One end of the control coil of the double-pole double-throw relay K1 is connected to the power supply VCC, and the other end is connected to the collector of the drive control transistor Q1, two normally closed static contacts are respectively connected to the input end and the output end of the analog signal, two moving contacts are respectively connected to the interface of the sensor under test, one normally open static contact is connected to the digital signal end, and the other normally open static contact is grounded;

[0020] The base of the driving control transistor Q1 is connected to the I / O pin of the main control microprocessor through a resistor R9, and the emitter is grounded;

[0021] The indicator light LED1 is connected to the base of the driving control transistor Q1 through the resistor R9, and is connected to the power supply VCC through the resistor R8;

[0022] The indicator light LED2 is connected to the base of the driving control transistor Q1 through the resistor R9 and is grounded through the resistor R10.

[0023] The advantages of the present invention are as follows: the direct current power supply of the present invention is a single power supply of the automatic test system, the constant current source circuit provides energy for the tested sensor of the automatic test system when it works in a simulation state, a reasonable digital-analog switching circuit design is adopted, and the test system does not need to adopt negative power supply logic power supply during operation, and can be used normally without negative signal conversion, the circuit design is simple, the test system adopts a main control microprocessor to control test instructions and process data, and integrates a human-computer interaction circuit (including buttons and display windows) to realize human-computer interaction, thereby ensuring that the test system can still perform testing work when there is no host computer; the present invention has the advantages of intuitive data output, stable system operation, simple measurement, etc., and can be said to fill the gap in the domestic and foreign markets.

Brief Description of the Drawings

[0024] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0025] Figure 1 It is the structural block diagram of the existing data acquisition system of IEEE1451.4 common signal line type intelligent sensor;

[0026] Figure 2 It is a schematic diagram of the simplified circuit structure of the automatic test system of the present invention.

[0027] Figure 3 It is a principle structure block diagram of the test system of the present invention;

[0028] Figure 4 It is a structural schematic diagram of a digital-to-analog port switching circuit of a test system of the present invention;

[0029] Figure 5 It is a structural schematic diagram of a USB to serial port circuit of a test system of the present invention;

[0030] Figure 6 It is a flow chart of the testing process of the testing system of the present invention. [Specific implementation method]

[0031] The embodiment of the present invention provides an IEEE1451.4 common signal line type intelligent sensor automatic test system, which adopts a single power supply and can be used normally without negative power supply signal conversion for data processing. The circuit design is simple, and the test system integrates buttons and display windows, which can ensure that the system can still perform testing work when there is no host computer.

[0032] The technical solution in the embodiment of the present invention is to solve the above problems. The overall idea is as follows: a single power supply is used instead of a negative power supply logic power supply. Data processing can be used normally without negative power supply signal conversion. The circuit design is simple. The test system uses a main control microprocessor to control test instructions and process data, and integrates a human-computer interaction circuit (including buttons and display windows) to achieve human-computer interaction, thereby ensuring that the test system can still perform testing work when there is no host computer. It has the advantages of intuitive data output, stable system operation, and simple measurement.

[0033] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] See also Figures 1 to 6 As shown, the automatic test system of the present invention is used to test IEEE1451.4 common signal line type intelligent sensors. It includes: power input interface, constant current source circuit, digital-analog port switching circuit, DCtoDC step-down voltage stabilization circuit, main control microprocessor, human-computer interaction circuit and tested sensor interface;

[0035] The power input interface is respectively connected to the constant current source circuit and the DCtoDC step-down voltage stabilizing circuit; the constant current source circuit, the digital-analog port switching circuit and the interface of the sensor under test are connected in sequence; the DCtoDC step-down voltage stabilizing circuit is respectively connected to the digital-analog port switching circuit, the main control microprocessor and the human-computer interaction circuit; the main control microprocessor is also respectively connected to the digital-analog port switching circuit and the human-computer interaction circuit;

[0036] The power input interface inputs a DC power supply to power the constant current source circuit and the DCtoDC step-down voltage stabilization circuit; the DC power supply is a single power supply for the automatic test system;

[0037] The constant current source circuit generates a variable constant current source for the sensor under test to work in the analog function;

[0038] The digital-analog port switching circuit performs a switching function between the analog function execution circuit and the digital function execution circuit during the test process;

[0039] The DCtoDC step-down voltage stabilization circuit converts the DC voltage into the normal operating voltage of the main control microprocessor, the human-computer interaction circuit, and the digital-to-analog port switching circuit respectively;

[0040] The main control microprocessor performs test instruction control and data processing;

[0041] The human-computer interaction circuit provides a human-computer interaction function;

[0042] The sensor interface to be tested is connected to the intelligent sensor to be tested.

[0043] The automatic test system of the present invention further comprises an audible and visual alarm circuit, which is respectively connected to the DCtoDC step-down voltage stabilization circuit and the main control microprocessor, and alarms when an abnormal state occurs during the automatic test process;

[0044] The automatic test system of the present invention also includes a USB to serial port circuit, which is respectively connected to the DCtoDC step-down voltage stabilization circuit and the main control microprocessor to download the compiled system software to the main control microprocessor.

[0045] The USB to serial port circuit specifically includes a USB interface, a low-pass filter, a communication conversion chip, a serial port data external interface and a serial port output high level selection circuit;

[0046] The VDDIO pin of the communication conversion chip is connected to the serial port output high level selection circuit, and the TX pin is connected to the serial port data external interface through the diode D5 and the resistor 18 in sequence.

[0047] The USB to serial port circuit specifically also includes an anti-static protection circuit and a short-circuit protection circuit. The anti-static protection circuit is connected to the USB interface, and the short-circuit protection circuit is respectively connected to the USB interface, the anti-static protection circuit and the low-pass filter.

[0048] The digital-to-analog port switching circuit specifically includes a double-pole double-throw relay K1, a drive control transistor Q1, an indicator light LED1 and an indicator light LED2;

[0049] One end of the control coil of the double-pole double-throw relay K1 is connected to the power supply VCC, and the other end is connected to the collector of the drive control transistor Q1, two normally closed static contacts are respectively connected to the input end and the output end of the analog signal, two moving contacts are respectively connected to the interface of the sensor under test, one normally open static contact is connected to the digital signal end, and the other normally open static contact is grounded;

[0050] The base of the driving control transistor Q1 is connected to the I / O pin of the main control microprocessor through a resistor R9, and the emitter is grounded;

[0051] The indicator light LED1 is connected to the base of the driving control transistor Q1 through the resistor R9, and is connected to the power supply VCC through the resistor R8;

[0052] The indicator light LED2 is connected to the base of the driving control transistor Q1 through the resistor R9 and is grounded through the resistor R10.

[0053] like Figure 6 As shown, the test process of the self-test system of the present invention is as follows:

[0054] After the operator connects and powers on the test system, the smart sensor is connected to the corresponding interface of the sensor to be tested. By default, the initial state of the test system is analog test mode. After confirming that the wiring is correct, just press the test button, the test system will automatically switch to digital test mode and read the relevant content data of the TEDS chip inside the smart sensor. After the reading is successful, the key data after reading will be displayed on the LCD screen of the system human-computer interaction circuit for the operator to monitor the data. After the reading is completed, it will switch back to analog test mode again. If the reading fails three times in a row, the test system will issue an audible and visual alarm through the audible and visual alarm circuit and automatically switch back to analog test mode. If the write protection of the smart sensor is not turned on, the operator can adjust and modify the read data by pressing the button, and then rewrite the modified data into the sensor through the programming button. During the test, LED1 and LED2 light up, indicating that the current test system is in analog test mode and digital test mode respectively.

[0055] The implementation process of the self-test system of the present invention is as follows:

[0056] Step 1: Fix the electronic components to the circuit board through SMT and other welding technologies to form a circuit board that can work normally;

[0057] Step 2: Based on the STC8A8K64S4A12 microprocessor hardware platform, use C language to integrate and compile the driver of the communication protocol for reading and writing TEDS data, the key functions, the LCD display driver, and the control logic of the digital-to-analog switch;

[0058] Step 3: Download the designed and compiled software program to the microprocessor on the circuit board through the USB interface of the computer to form an IEEE1451.4 common signal line type intelligent sensor automatic test system with specified functions.

[0059] The advantages of the present invention are as follows: the direct current power supply of the present invention is a single power supply of the automatic test system, the constant current source circuit provides energy for the tested sensor of the automatic test system when it works in a simulation state, a reasonable digital-analog switching circuit design is adopted, and the test system does not need to adopt negative power supply logic power supply during operation, and can be used normally without negative signal conversion, the circuit design is simple, the test system adopts a main control microprocessor to control test instructions and process data, and integrates a human-computer interaction circuit (including buttons and display windows) to realize human-computer interaction, thereby ensuring that the test system can still perform testing work when there is no intervention of a host computer; the present invention has the advantages of intuitive data output, stable system operation, simple measurement, etc., and can be said to fill the gap in the domestic and foreign markets.

[0060] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. An automatic test system for IEEE1451.4 common signal line type intelligent sensor, characterized in that: It includes a power input interface, a constant current source circuit, a digital-analog port switching circuit, a DCtoDC step-down voltage stabilization circuit, a main control microprocessor, a human-computer interaction circuit and a sensor interface under test; The power input interface is respectively connected to the constant current source circuit and the DCtoDC step-down voltage stabilizing circuit; the constant current source circuit, the digital-analog port switching circuit and the interface of the sensor under test are connected in sequence; the DCtoDC step-down voltage stabilizing circuit is respectively connected to the digital-analog port switching circuit, the main control microprocessor and the human-computer interaction circuit; the main control microprocessor is also respectively connected to the digital-analog port switching circuit and the human-computer interaction circuit; The power input interface inputs a DC power supply to power the constant current source circuit and the DCtoDC step-down voltage stabilization circuit; the DC power supply is a single power supply for the automatic test system; The constant current source circuit generates a variable constant current source for the sensor under test to work in the analog function; The digital-analog port switching circuit performs a switching function between the analog function execution circuit and the digital function execution circuit during the test process; The DCtoDC step-down voltage stabilization circuit converts the DC voltage into the normal operating voltage of the main control microprocessor, the human-computer interaction circuit, and the digital-to-analog port switching circuit respectively; The main control microprocessor performs test instruction control and data processing; the human-computer interaction circuit provides a human-computer interaction function; The sensor interface to be tested is connected to the intelligent sensor to be tested; The digital-to-analog port switching circuit specifically includes a double-pole double-throw relay K1, a drive control transistor Q1, an indicator light LED1 and an indicator light LED2; One end of the control coil of the double-pole double-throw relay K1 is connected to the power supply VCC, and the other end is connected to the collector of the drive control transistor Q1, two normally closed static contacts are respectively connected to the input end and the output end of the analog signal, two moving contacts are respectively connected to the interface of the sensor under test, one normally open static contact is connected to the digital signal end, and the other normally open static contact is grounded; The base of the driving control transistor Q1 is connected to the I / O pin of the main control microprocessor through a resistor R9, and the emitter is grounded; The indicator light LED1 is connected to the base of the driving control transistor Q1 through the resistor R9, and is connected to the power supply VCC through the resistor R8; The indicator light LED2 is connected to the base of the driving control transistor Q1 through the resistor R9 and is grounded through the resistor R10.

2. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 1, characterized in that: It also includes an audible and visual alarm circuit, which is respectively connected to the DCtoDC step-down and voltage stabilizing circuit and the main control microprocessor, and alarms when an abnormal state occurs during the automatic test process.

3. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 1, characterized in that: It also includes a USB to serial port circuit, which is connected to the DCtoDC step-down and voltage stabilization circuit and the main control microprocessor respectively, and downloads the compiled system software to the main control microprocessor.

4. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 3, characterized in that: The USB to serial port circuit specifically includes a USB interface, a low-pass filter, a communication conversion chip, a serial port data external interface and a serial port output high level selection circuit; The D+ and D- pins of the USB interface are connected to the communication conversion chip through the low-pass filter; the VDDIO pin of the communication conversion chip is connected to the serial port output high level selection circuit, and the TX pin is connected to the serial port data external interface through the diode D5 and the resistor 18 in sequence.

5. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 1, characterized in that: The USB to serial port circuit specifically also includes an anti-static protection circuit and a short-circuit protection circuit. The anti-static protection circuit is connected to the USB interface, and the short-circuit protection circuit is respectively connected to the USB interface, the anti-static protection circuit and the low-pass filter.

6. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 1, characterized in that: The power input interface, the constant current source circuit, the digital-to-analog port switching circuit, the DCtoDC step-down and voltage stabilization circuit, the main control microprocessor, the human-computer interaction circuit and the interface of the sensor under test are all arranged on a double-sided SMD circuit board.

7. The automatic test system of the IEEE1451.4 common signal line type intelligent sensor as claimed in claim 1, characterized in that: The DC power inputted by the power input interface is 18V-32V; the constant current source circuit generates a variable constant current source of 2-20mA.

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