Frequency signal generation method based on RS485 serial port and rotating speed system test method
阅读说明：本技术 一种基于rs485串口的频率信号生成方法及转速系统测试方法 (Frequency signal generation method based on RS485 serial port and rotating speed system test method ) 是由 管明华 姚琦 李莹莹 王孝峰 吴嘉舜 杨晓芳 代振威 于 2020-06-28 设计创作，主要内容包括：一种基于RS485串口的频率信号生成方法及转速系统测试方法,其中,频率信号生成方法包括：将RS485芯片的DE端和端连接,并与控制模块的第一输出端连接；以及将RS485芯片的DI端与控制模块的第二输出端连接；利用所述控制模块中预设的控制程序控制所述第一输出端和所述第二输出端的电位变化,从而控制所述RS485芯片的输出端输出相应的频率信号。转速系统的测试方法包括：利用所述转速系统中的RS485接口电路生成转速模拟信号；通过所述转速模拟信号测试所述转速系统。本发明提出的频率信号生成方法能够产生多种形式的频率信号；在此基础上提出的转速系统的测试方法,可以利用现有控制系统中的RS485电路,并且不需要外接电源,从而更加方便了现场的测试工作。(A frequency signal generation method and a rotating speed system test method based on an RS485 serial port are disclosed, wherein the frequency signal generation method comprises the following steps: connecting the DE end and the DE end of the RS485 chip, and connecting the DE end and the DE end with a first output end of a control module; connecting the DI end of the RS485 chip with the second output end of the control module; and controlling the potential change of the first output end and the second output end by using a preset control program in the control module, so as to control the output end of the RS485 chip to output corresponding frequency signals. The test method of the rotating speed system comprises the following steps: generating a rotating speed analog signal by utilizing an RS485 interface circuit in the rotating speed system; and testing the rotating speed system through the rotating speed analog signal. The frequency signal generation method provided by the invention can generate frequency signals in various forms; the test method of the rotating speed system provided on the basis can utilize the RS485 circuit in the existing control system, and does not need an external power supply, thereby being more convenient for the field test work.)
1. A frequency signal generation method based on an RS485 serial port is characterized by comprising the following steps:
the DE end of an RS485 chip is connected with
connecting the DI end of the RS485 chip with the second output end of the control module;
and controlling the potential change of the first output end and the second output end by using a preset control program in the control module, so as to control the output end of the RS485 chip to output corresponding frequency signals.
2. The method for generating a frequency signal according to claim 1, wherein an output terminal of the RS485 chip is divided into a positive output terminal and a negative output terminal, the method further comprising:
and a resistor is arranged in parallel between the positive output end and the negative output end of the RS485 chip and used for filtering.
3. The frequency signal generation method of claim 1, wherein the control module comprises: a single chip microcomputer or an ARM.
4. A method of testing a rotational speed system, comprising:
generating a rotating speed analog signal by utilizing an RS485 interface circuit in the rotating speed system;
and testing the rotating speed system through the rotating speed analog signal.
5. A method for testing a tachometer system according to claim 4, wherein the generating a tachometer analog signal using an RS485 interface circuit in the tachometer system comprises:
set up interim test circuit, set up interim test circuit includes:
the DE end and the DE end of the RS485 chip are respectively connected with a first output end of an idle control module in an external control module or a system to be testedA terminal;
the second output end of the idle control module in the external control module or the system to be tested is connected with the DI end of the RS485 chip;
and disconnecting the positive output end and the negative output end of the RS485 chip from an external communication circuit, and connecting the positive output end and the negative output end of the RS485 chip into the rotating speed system.
6. A method for testing a tachometer system according to claim 5, wherein the generating a tachometer analog signal using an RS485 interface circuit in the tachometer system further comprises:
initializing the test circuit, the initializing the test circuit comprising:
configuring the first output end and the second output end of the control module to be general IO ports;
setting a generated waveform mode and the number of tooth-missing waveforms;
calculating the period of a timer to realize the generation of a rotating speed analog signal with a specific frequency;
configuring a timer and enabling timed interruption;
and executing a preset interrupt program to enable the test circuit to generate a waveform mode and output a rotating speed analog signal according to the set generated waveform mode and the number of the tooth-missing waveforms.
7. A method for testing a rotational speed system according to claim 6, wherein the executing a preset interrupt routine to make the test circuit output a rotational speed analog signal according to the set generated waveform pattern and the number of missing tooth waveforms comprises:
generating a tooth-missing waveform signal, a positive amplitude waveform signal or a negative amplitude waveform signal according to a preset waveform mode in an interrupt period;
adding 1 to the preset waveform count every time one tooth-missing waveform signal, positive amplitude waveform signal or negative amplitude waveform signal is generated;
judging whether the waveform count is larger than the preset number of the tooth-missing waveforms;
responding to the condition that whether the waveform count is larger than the preset number of the tooth-missing waveforms or not is judged to be yes, and clearing the waveform count;
and finishing the timed interruption of the current period, and timing to enter the timed interruption of the next period.
8. A method of testing a speed system according to claim 7, wherein the speed analog signal is comprised of one or more of the missing tooth waveform signal, the positive amplitude waveform signal, and the negative amplitude waveform signal generated for a plurality of interrupt periods.
9. A method of testing a rotational speed system according to claim 8, wherein the missing tooth waveform signal, the positive-amplitude waveform signal, and the negative-amplitude waveform signal are square wave signals;
and the amplitude of the tooth-missing waveform is zero, and no signal is output in an interrupt period for generating the tooth-missing waveform signal.
10. A method for testing a speed system according to any one of claims 7-9, wherein said generating a missing tooth waveform signal, a positive amplitude waveform signal or a negative amplitude waveform signal according to a predetermined waveform pattern during an interrupt period comprises:
the control module is used for controlling the power supply according to a preset waveform mode
Controlling the first output port to be set at a low level, and controlling the second output port to be set at a low level, so as to control the output end of the RS485 chip to output a missing tooth waveform signal; alternatively, the first and second electrodes may be,
controlling the first output port to be set at a high level, and controlling the second output port to be set at a high level, so as to control the output end of the RS485 chip to output a forward amplitude waveform signal; alternatively, the first and second electrodes may be,
and controlling the first output port to be set at a high level and the second output port to be set at a low level, so as to control the output end of the RS485 chip to output a negative amplitude waveform signal.
Technical Field
The invention relates to the field of system test, in particular to a frequency signal generation method and a rotating speed system test method based on an RS485 serial port, which are used for facilitating field debugging of a system to be tested and saving debugging cost.
Background
In the process of development, debugging and field service in the field of automatic control, a means for testing the function of an embedded control system (hereinafter referred to as a control system) by using a simulation signal is very common and effective. The frequency input signal is a common signal of the control system, and is generally used for detecting physical parameters such as a rotating speed. The frequency quantity signal is usually in the form of a square wave signal and a sine wave signal, and usually needs to be generated by a waveform generator or a special simulation instrument. However, signal generating devices such as waveform generators are generally large in size, expensive and inconvenient to carry, and may need an external power supply when applied in the field, thereby causing inconvenience to field testing work.
Disclosure of Invention
In order to solve the problems in the prior art mentioned in the background art, the invention provides a frequency signal generation method based on an RS485 serial port, which comprises the following steps: connecting the DE end and the DE end of the RS485 chip, and connecting the DE end and the DE end with a first output end of a control module; connecting the DI end of the RS485 chip with the second output end of the control module; and controlling the potential change of the first output end and the second output end by using a preset control program in the control module, so as to control the output end of the RS485 chip to output corresponding frequency signals.
In one or more embodiments, the output terminal of the RS485 chip is divided into a positive output terminal and a negative output terminal, and the frequency signal generating method further includes: and a resistor is arranged in parallel between the positive output end and the negative output end of the RS485 chip and used for filtering.
In one or more embodiments, the control module comprises: a single chip microcomputer or an ARM.
Under the same inventive concept, the invention also provides a test method of the rotating speed system, which comprises the following steps: generating a rotating speed analog signal by utilizing an RS485 interface circuit in the rotating speed system; and testing the rotating speed system through the rotating speed analog signal.
In one or more embodiments, the generating a rotation speed analog signal by using an RS485 interface circuit in the rotation speed system includes: set up interim test circuit, set up interim test circuit includes: the first output end of an idle control module in an external control module or a system to be tested is respectively connected with the DE end and the end of the RS485 chip; the second output end of the idle control module in the external control module or the system to be tested is connected with the DI end of the RS485 chip; and disconnecting the positive output end and the negative output end of the RS485 chip from an external communication circuit, and connecting the positive output end and the negative output end of the RS485 chip into the rotating speed system.
In one or more embodiments, the generating a rotation speed analog signal by using an RS485 interface circuit in the rotation speed system further includes: initializing the test circuit, the initializing the test circuit comprising: configuring the first output end and the second output end of the control module to be general IO ports; setting a generated waveform mode and the number of tooth-missing waveforms; calculating the period of a timer to realize the generation of a rotating speed analog signal with a specific frequency; configuring a timer and enabling timed interruption; and executing a preset interrupt program to enable the test circuit to generate a waveform mode and output a rotating speed analog signal according to the set generated waveform mode and the number of the tooth-missing waveforms.
In one or more embodiments, the executing a preset interrupt program to enable the test circuit to output a rotation speed analog signal according to the set generated waveform mode and the number of the missing tooth waveforms includes: generating a tooth-missing waveform signal, a positive amplitude waveform signal or a negative amplitude waveform signal according to a preset waveform mode in an interrupt period; adding 1 to the preset waveform count every time one tooth-missing waveform signal, positive amplitude waveform signal or negative amplitude waveform signal is generated; judging whether the waveform count is larger than the preset number of the tooth-missing waveforms; responding to the condition that whether the waveform count is larger than the preset number of the tooth-missing waveforms or not is judged to be yes, and clearing the waveform count; and finishing the timed interruption of the current period, and timing to enter the timed interruption of the next period.
In one or more embodiments, the rotation speed analog signal is composed of one or more of the missing tooth waveform signal, the positive amplitude waveform signal and the negative amplitude waveform signal generated in a plurality of interrupt periods.
In one or more embodiments, the missing tooth waveform signal, the positive amplitude waveform signal, and the negative amplitude waveform signal are all square wave signals; and the amplitude of the tooth-missing waveform is zero, and no signal is output in an interrupt period for generating the tooth-missing waveform signal.
In one or more embodiments, the generating a tooth-missing waveform signal, a positive amplitude waveform signal, or a negative amplitude waveform signal according to a preset waveform pattern in an interrupt period includes: the control module is used for controlling the power supply according to a preset waveform mode
Controlling the first output port to be set at a low level, and controlling the second output port to be set at a low level, so as to control the output end of the RS485 chip to output a missing tooth waveform signal; alternatively, the first and second electrodes may be,
controlling the first output port to be set at a high level, and controlling the second output port to be set at a high level, so as to control the output end of the RS485 chip to output a forward amplitude waveform signal; alternatively, the first and second electrodes may be,
and controlling the first output port to be set at a high level and the second output port to be set at a low level, so as to control the output end of the RS485 chip to output a negative amplitude waveform signal.
The frequency signal generation method provided by the invention can generate frequency signals in various forms, not only meets various requirements of a system to be tested on test signals, but also facilitates field debugging work. On the basis, the invention also provides a test method of the rotating speed system, which utilizes the rotating speed system to generate the test signal, thereby not only avoiding the use of an additional frequency signal generating device (such as a waveform generator or a special simulation instrument and the like), reducing the debugging cost, but also not needing an external power supply, and bringing convenience to the field test work.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other embodiments can be obtained by using the drawings without creative efforts.
Fig. 1 is a working flow chart of a frequency signal generation method based on an RS485 serial port according to the present invention;
fig. 2 is a schematic structural diagram of a frequency signal generating device based on an RS485 serial port according to the present invention;
FIG. 3 is a flowchart illustrating the testing operation of a rotational speed system according to the present invention;
FIG. 4 is a flowchart illustrating the operation of generating a rotational speed analog signal according to the present invention;
FIG. 5 is a flow chart of the work of setting up a temporary test circuit of the present invention;
FIG. 6 is a flowchart illustrating the initialization of the test circuit according to the present invention;
FIG. 7 is a flowchart illustrating operation of an interrupt routine according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a positive amplitude square wave;
FIG. 9 is a schematic diagram of positive and negative amplitude square waves;
fig. 10 is a schematic diagram of a missing tooth square wave.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments of the present invention are described in further detail with reference to the accompanying drawings.
It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are used for distinguishing two entities with the same name but different names or different parameters, and it should be noted that "first" and "second" are merely for convenience of description and should not be construed as limitations of the embodiments of the present invention, and they are not described in any more detail in the following embodiments.
For the technical problems existing in the background technology, analysis shows that a system to be tested has a large number of interface circuits, and if the interface circuits can be used for generating analog signals with specific frequencies, the problems can be well solved.
The frequency signal generation method utilizes the RS485 interface circuit commonly existing in a system to be tested, and enables the RS485 interface circuit to output square wave signals with positive, negative or zero amplitude values by building a temporary circuit and a preset control program, so that the square wave signals are utilized to simulate corresponding test frequency signals. The specific method is as follows:
as shown in fig. 1, it is a flowchart of a method for generating a frequency signal based on an RS485 serial port according to the present invention. The working process of the frequency signal generation method comprises the following steps: step 10, adding the DE end of the RS485 chip to
The frequency signal generation method can generate frequency signals in various forms, and can meet various requirements of different systems to be tested on test signals. The device structure corresponding to the frequency signal generation method is as follows:
as shown in fig. 2, it is a schematic structural diagram of a frequency signal generating device based on an RS485 serial port. Wherein, frequency signal generation device includes: control module, RS485 chip. Specifically, DE terminal of RS485 chip and
Furthermore, the control module comprises an embedded system such as a single chip microcomputer or an ARM and the like, the structure is compact, I/O ports are abundant, and the transmission requirements of different signals can be met. Optionally, the singlechip or the ARM comes from the outside of the system to be tested, and the method has the advantages that the configuration of the preset control program is not limited by the field; preferably, an idle single chip microcomputer or ARM in the system is adopted, so that only a temporary test circuit needs to be built on site, and a preset control program prepared in advance is burnt into the corresponding single chip microcomputer or ARM, and the method is more flexible and convenient.
Furthermore, in the I/O port of the control module, in order to switch the control mode of the RS485 circuit from the serial port of the single chip and the register thereof to I/O control and timer control, a serial data transceiving control terminal (i.e., IO1 terminal) of the single chip or ARM is respectively connected with the DE terminal and the RS485 chip
Further, the principle of the frequency signal generating apparatus of the present invention includes: when DE is terminated withWhen the terminals are all set at a low level, the voltage between the output terminal A and the output terminal B is 0V; when DE is terminated withWhen the terminals are all set to be at high level and the DI terminal is set to be at high level, a forward voltage is between the output terminal A and the output terminal B, and the amplitude range is about +2 to + 6V; when DE is terminated withWhen the terminals are all set to high level and the DI terminal is set to low level, a negative voltage is between the output terminal A and the output terminal B, and the amplitude range is about-2V to-6V. On the basis, a timer of a singlechip system or an ARM system is controlled to generate timing interruption through a control program preset in a singlechip chip or the ARM chip, and a DI end, a DE end and a DI end are controlled through the programThe terminal is provided with a designated level signal, and the required frequency signals can be controlled to be generated at the positive output end A and the negative output end B of the RS485 circuit. The output end of the frequency signal generating device can generate positive amplitude waveforms, negative amplitude waveforms and zero amplitude (missing teeth) waveforms, so that frequency signals in various forms can be generated in a controllable frequency range to meet the test requirements of different systems to be tested. For example, the output of the tooth-missing square wave signal is used for simulating a rotating speed signal, and further used for testing a rotating speed system. In an embodiment of the present application, a method for testing a rotational speed system is provided, which includes the following steps:
fig. 3 is a flowchart illustrating a test operation of the rotational speed system according to the present invention. The testing work flow of the rotating speed system comprises the following steps:
Further, in an embodiment of the present invention,
Further, as shown in fig. 5, a working flow chart for building the temporary test circuit of the present invention is shown. In one embodiment of the invention, the building of the temporary test circuit of step 1.1 comprises: step 1.11, respectively connecting the DE end of the RS485 chip with the DE end of the RS485 chip through the external control module or the first output end of the idle control module in the system to be tested
Further, the control module in the system under test generally includes: one or more of a singlechip, an ARM or a CPU. When the control module is a single chip microcomputer or an ARM, in order to switch the control mode of the RS485 circuit from the serial port and the register of the single chip microcomputer to IO control and timer control, preferably, the serial data transceiving control end of the single chip microcomputer or the ARM is used as a first output end to be respectively connected with the DE end and the DE end of the RS485 chip
Further, as shown in fig. 6, it is a flowchart for initializing the test circuit of the present invention. In one embodiment of the invention, the initialization workflow of step 1.2 comprises: step 1.21, start; step 1.22, configuring a serial data receiving and transmitting control end (IO1 end) and a serial data transmitting end (IO2 end) of the single chip microcomputer or the ARM as a universal I/O port; step 1.23, setting a generated waveform mode and the number of tooth-missing waveforms; step 1.24, calculating the period of a timer to realize the generation of a rotating speed analog signal with specific frequency; step 1.25, configuring a timer; step 1.26, enabling timed interruption; step 1.27, the initialization is completed and waits.
Further, for step 1.3. In one embodiment of the present invention, the workflow of the interrupt routine for generating the tachometer simulation signal to test the tachometer system is as follows:
fig. 7 is a flowchart illustrating the operation of an embodiment of the interrupt routine of the present invention. Wherein the workflow comprises:
1) the process proceeds to the flow 100 periodically, and then to the interrupt flow, and the initial value n of the configuration waveform count n is set to 0.
2) Entering a process 200, and judging whether to generate a tooth-missing waveform according to a preset waveform mode; if yes, go to flow 400; otherwise, flow 300 is entered.
3) Entering a flow 300, and judging a waveform mode to be generated; if a positive amplitude square wave is to be generated, the process proceeds to flow 310; if a positive and negative amplitude square wave is to be generated, flow 320 is entered.
4) Entering the process 310, determining the waveform to be generated; when a positive amplitude waveform is to be generated, the process proceeds to step 311; when a zero amplitude waveform (missing tooth waveform) is to be generated, flow 312 is entered.
5) Entering the flow 311, the control IO1 and the IO2 output levels: IO1 is 1, IO2 is 1; flow 400 is entered.
6) Flow 312 is entered, and IO1 and IO2 output levels are controlled: IO1 is 0, IO2 is 0; flow 400 is entered.
7) Entering a flow 320, and judging a waveform to be generated; if a positive amplitude waveform is to be generated, the process proceeds to a flow 321; if a negative amplitude waveform is to be generated, then flow 322 is entered; if a zero amplitude waveform (missing tooth waveform) is to be generated, flow 323 is entered.
8) Flow 321 is entered, and IO1 and IO2 output levels are controlled: IO1 is 1, IO2 is 1; flow 400 is entered.
9) Flow 322 is entered, and IO1 and IO2 output levels are controlled: IO1 is 1, IO2 is 0; flow 400 is entered.
10) Entering a flow 323, controlling output levels of IO1 and IO 2: IO1 is 0, IO2 is 0; flow 400 is entered.
11) The process proceeds to the flow 400, and determines whether to generate a complete waveform simulation through the operation cycle (the waveform includes: positive amplitude waveforms, negative amplitude waveforms, and zero amplitude waveforms (missing tooth waveforms)); if yes, enter flow 500; otherwise, flow 600 is entered.
12) Entering the process 500, the waveform count n is incremented by 1, i.e., n is equal to n + 1.
13) Entering a flow 600, and determining whether the number of finished waveforms is greater than a preset number of missing-tooth waveforms (the preset number of missing-tooth waveforms is configured in initialization); if so, enter flow 700; otherwise, flow 800 is entered.
14) Entering the flow 700, and resetting the waveform count n, that is, making n equal to 0; and then proceeds to process 800.
15) And entering a flow 800, jumping out of the interrupt program, and timing to prepare entering the next interrupt period.
In the present embodiment, the tooth-missing waveform is generated according to a preset rule, optionally, such as periodically, or preferably, such as randomly, to simulate a rotation speed signal more truly; by the method, special signal generating equipment or simulation equipment does not need to be purchased or carried, so that the field development and debugging cost is reduced, and the debugging efficiency is improved.
It should be noted that, when power is turned on, the I01 port and the I02 port are both at low level, and at this time, if a missing tooth waveform (zero amplitude waveform) needs to be generated according to a preset waveform mode, the step 400 may be directly performed; when the interrupt program is exited, the I01 port and the I02 port both return low.
In addition, the invention is not limited to the test of the rotating speed system, and any test system capable of testing by using square wave signals can be tested by using the method of the invention.
In addition, the square wave signal output by the invention can be further converted into triangular wave or sine wave through a corresponding electric element or circuit, so that any system capable of utilizing triangular wave or sine wave to test can be tested.
In the test of the speed control system, the working conditions to be tested comprise: starting, dynamic conditions, steady state conditions, and stopping of the engine. The rotating speed signals corresponding to the working conditions can be respectively formed by combining one or more square waves shown in fig. 8 to 10. Wherein, fig. 8 is a schematic diagram of a positive amplitude square wave; FIG. 9 is a schematic diagram of positive and negative amplitude square waves; fig. 10 is a schematic diagram of a missing tooth square wave. In fig. 8 and 9, there are (i) a positive amplitude waveform, (ii) a negative amplitude waveform, and (iii) a zero amplitude waveform (a missing tooth waveform).
It should be noted that the square waves shown in fig. 8-10 are merely examples of square waves formed by positive amplitude waveforms, negative amplitude waveforms, and missing tooth waveforms; any square wave which can be formed by a positive amplitude waveform, a negative amplitude waveform and a tooth-missing waveform can be controlled and generated through a preset waveform mode within a controllable frequency range.
In another embodiment of the present invention, there is also provided a method of randomly generating a missing tooth waveform, the method including: increasing a random number K and a generating program thereof, presetting a divisor f, wherein f is a positive integer, setting S to be (K + n)/f, and generating a tooth missing waveform in the n +1 th waveform when S is the positive integer; where n is the waveform count, the parameter f may be configured in an initialization step.
The foregoing is an exemplary embodiment of the present disclosure, but it should be noted that various changes and modifications could be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the disclosed embodiments described herein need not be performed in any particular order. Furthermore, although elements of the disclosed embodiments of the invention may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.
It should be understood that, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly supports the exception. It should also be understood that "and/or" as used herein is meant to include any and all possible combinations of one or more of the associated listed items.
The numbers of the embodiments disclosed in the embodiments of the present invention are merely for description, and do not represent the merits of the embodiments.
Those of ordinary skill in the art will understand that: the discussion of any embodiment above is meant to be exemplary only, and is not intended to intimate that the scope of the disclosure, including the claims, of embodiments of the invention is limited to these examples; within the idea of an embodiment of the invention, also technical features in the above embodiment or in different embodiments may be combined and there are many other variations of the different aspects of the embodiments of the invention as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, substitutions, improvements, and the like that may be made without departing from the spirit and principles of the embodiments of the present invention are intended to be included within the scope of the embodiments of the present invention.