CN106444606B - Incremental electronic coded odometer device based on PLC technology and its application - Google Patents

Abstract

The invention relates to an incremental electronic coded odometer device based on PLC technology and its application. The device is installed on a tram, and the odometer device is connected with the wheel speed sensor and the speed feedback voltage sensor of the tram respectively. Connect with vehicle-mounted controller, described odometer device comprises incremental encoder module, AD conversion module, PLC module, incremental pulse generator module, and described PLC module is connected with incremental encoder module, AD conversion module respectively , the incremental pulse generator module is connected, the incremental encoder module is connected with the wheel speed sensor, the AD conversion module is connected with the speed feedback voltage sensor, and the incremental pulse generator module is connected with the vehicle control device connection. Compared with the prior art, the present invention has the advantages of greatly enhanced scalability and the like.

Description

Incremental electronic coded odometer device based on PLC technology and its application

technical field

The invention relates to an incremental electronic coding odometer, in particular to an incremental electronic coding odometer device based on PLC technology and its application.

Background technique

The on-board control system (OBS) of the train in the tram signal system is extremely important. The on-board functions of the tram train include the ATP train automatic protection of the tram and the DAC train assisted driving, regardless of whether it is the ATP function or the DAC. The functions are all dependent on the speed measurement and positioning information of the train, and the odometer speed measurement and beacon positioning are required respectively. Among them, the current train odometers are basically monopolized by foreign companies, which have disadvantages such as opaque technology, high price, inflexible use, high equipment loss, and poor scalability. Therefore, in actual use, it is difficult to match one odometer to all types of vehicles, and constant adjustment and correction are required in actual installation and use.

In actual use, due to various reasons, there are still some technical problems in the research and development of coded odometer at home and abroad:

1) Scalability: As the demand for rail transit continues to increase, the complexity of different road conditions and lines is also increasing. Therefore, the demand for coded odometers in trains is also increasing. The traditional Hall-type coded odometer And photoelectric coded odometers are difficult to adapt to many different scenarios.

2) Versatility: The current rail transit is divided into three aspects: national railway, urban rail transit, and tram. Coding the odometry is necessary.

3) Loss: The traditional coded odometer has the rotation and friction of mechanical parts. During the accumulated train operation, the mechanical parts will be worn and corroded, which will not only affect the life of the mechanical parts, but also further affect the code. Accuracy and accuracy of the odometer.

4) Traceability: When a traditional coded odometer fails, it is difficult to detect the cause and time of the failure, and a dedicated odometer test unit must be used, and the detection effect is not very satisfactory.

5) Incremental conversion and recording: traditional coded odometers can only collect speed, without displacement recording and speed conversion functions.

Contents of the invention

The purpose of the present invention is exactly to provide a kind of incremental electronic coded odometer device and its application based on PLC technology in order to overcome the defective that above-mentioned prior art exists, on the basis of drawing on the insufficient experience of existing foreign coded odometer technology, Design a general-purpose PLC-type incremental electronic coded odometer, which can provide a stable and reliable data source for the collection of tram speed and positioning information, and provide reliable technical support and a convenient research platform for the tram signal system. Therefore it is of great significance.

The purpose of the present invention can be achieved through the following technical solutions:

An incremental electronically coded odometer device based on PLC technology, the device is installed on a tram, and the odometer device is respectively connected with a wheel speed sensor, a speed feedback voltage sensor and an on-board controller of the tram, The odometer device comprises an incremental encoder module, an AD conversion module, a PLC module, and an incremental pulse generator module, and the described PLC module is connected with the incremental encoder module, the AD conversion module, and the incremental pulse generator respectively. The incremental encoder module is connected with the wheel speed sensor, the AD conversion module is connected with the speed feedback voltage sensor, and the incremental pulse generator module is connected with the vehicle controller.

The incremental encoder module is a three-channel incremental encoder, and the encoder is provided with three signal outputs, namely: A pulse, B pulse and Z pulse, wherein the A pulse is in the front, the B pulse is in the back, and the A pulse is in the rear. There is a 90-degree difference from the B pulse, and a Z pulse is sent out per revolution as a reference mechanical zero position; the encoder rotates clockwise when viewed from the shaft end, that is, the A pulse is 90° ahead of the B pulse, and vice versa, the counterclockwise rotation is reverse rotation. That is, the B pulse leads the A pulse by 90°.

The AD conversion module is provided with four input channels and 32 registers, wherein four input channels are used to receive analog signals and convert them into digital quantities, and the allocation of 32 registers is defined as follows:

0#: channel initialization, the default value is H0000;

1#---4#: the average sampling number of channel 1---channel 4, which is used to obtain the average result;

5#---8#: The average input value of the sampling number of channel 1---channel 4, that is, the average value of all samples is obtained according to the average sampling times specified in #1---#4;

9#---12#: the current value read from channel 1---channel 4;

13#, 14#: reserved, not defined;

15#: Select A/D conversion speed, set to 0 to select normal speed; set to 1 to select high speed (15ms/channel);

16#---19#: reserved, not defined;

20#: reset to the default value and preset, the default value is 0;

21#: It is forbidden to adjust the offset and gain values;

22#: offset, gain adjustment;

23#: offset value, the default value is 0;

24#: Gain value, the default value is 5000;

25#---28#: reserved, not defined;

29#: error state;

30#: identification code K2010;

31#: disable.

The PLC module includes a CPU module, and the CPU module includes the following functions: timing interrupt collection, analog input collection and pulse control output.

The analog input acquisition includes sampling processing and averaging processing;

The adopting process is specifically: A/D conversion is performed on the analog input according to each scan of the CPU module, digital output is performed each time, and the value is stored in the digital output value, digital operation value and analog input value monitoring;

The average processing specifically includes: performing average processing on the digital output value for each channel, and storing the average value in the setting register.

There are three types of average processing, which are:

Time averaging: A/D conversion is performed according to the set time, the total value is averaged, and stored in the digital output value, digital operation value, and analog input value monitor; the number of processing within the set time varies with the scan time, and the number of processing = setting time/scanning time;

Count average: specify the average processing of the A/D conversion value by the number of times, digitally output the average value other than the maximum value and the minimum value, and store it in the digital output value, digital operation value, and analog input value monitor; based on the count average The time for the average value of the value to be stored in the digital output value, digital operation value and analog input value monitoring varies with the scan time; processing time = setting times × scan time;

Moving average: Specify the number of shift average processing times for the A/D conversion value, digitally output the average value, and store it in the digital output value, digital operation value, and analog input value monitor.

The pulse control output specifically includes: firstly, set the output port number and parameters, set the pulse output mode, and perform pulse output after selecting the PULSE/SIGN mode.

An application of an incremental electronic coded odometer device based on PLC technology, comprising the following steps:

1) When the PLC module is powered on, it enters the internal self-test stage of the PLC module, including the PLC module checking whether the hardware of the CPU module is normal, and resetting the monitoring timer;

2) PLC module initialization, that is, the PLC module loads the ladder diagram program, and initializes all timers and registers;

3) After the train starts running, the incremental encoder module tracks and collects the speed of the train wheel, and writes the speed and displacement information to the register in the CPU module of the PLC module according to the actual speed and displacement information;

4) After the train operation starts, if the train has a speed voltage output, the AD conversion module collects the speed voltage, and writes speed and displacement information to the register in the CPU module of the PLC module;

5) In the processing stage of the PLC module, the ladder diagram program is scanned sentence by sentence according to the steps of first up and then down and first left and then right, and logical operations are performed according to the results sampled into the input image register, and the operation results are stored in the relevant image in the register;

6) According to the program instructions, the CPU module of the PLC module converts the number of rotation cycles and speed analog voltage collected per unit time into speed pulse information according to the PLC instructions;

7) The PLC allocates new registers, writes the pulse number results, and sends pulse signals externally through the incremental pulse generator module;

8) Regularly send out the result of the number of pulses per unit time, indicating the displacement increment information per unit time.

Compared with the prior art, the present invention adopts PLC technology, and the electronic coding odometer can fully meet the requirements of the speed and position acquisition of the rail transit signal system, and has the advantages and characteristics as follows:

1) The scalability is greatly enhanced: the PLC incremental coded odometer, the basic unit is the PLC module, so it can be expanded to add other modules with different functions, such as serial port modules, network modules, various IO modules, etc., which can be convenient To adapt to the more demands of future trains on odometer;

2) Good versatility: Since the basic unit adopts the common PLC in the field of industrial control, it has a wide range of applications, and can be applied to different types of vehicles in rail transportation, such as rail bicycles, subways, high-speed rails, intercity railways, etc. ;

3) Low loss: the electronic coded odometer basically has no physical rotation and friction, and the average life of the PLC itself is 20 years, so the wear loss is very low, the life is long, and the use cost is reduced;

4) Traceability: PLC can record all the processed data, so when the train speed acquisition fails, the problem can be traced through the PLC log record;

5) Incremental conversion and recording: PLC incremental electronic coded odometer can accumulate and record the generated pulses, which can be directly converted into displacement incremental information and sent to the outside world, which can reduce the number of positioning beacons in rail transit;

6) Easy installation and maintenance: PLC is easy to install in the field of industrial control, and the PLC-type electronic odometer can be easily installed and used without changing the transmission mechanism of the train.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a work flow chart of the present invention;

Fig. 3 is the ladder diagram of PLC;

Figure 4 is a pulse output signal diagram of PULSE/SIGN mode.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

As shown in Figure 1, a kind of incremental electronic coding odometer device based on PLC technology, the device is installed on the tram, and the described odometer device is connected with the wheel speed sensor 6 and the speed feedback voltage of the tram respectively. Sensor 7 is connected with vehicle-mounted controller 5, and described odometer device comprises incremental encoder module 1, AD conversion module 2, PLC module 3, incremental pulse generator module 4, and described PLC module 3 is connected with increasing respectively. Quantity encoder module 1, AD conversion module 2, incremental pulse generator module 4 are connected, described incremental encoder module 1 is connected with wheel speed sensor 6, and described AD conversion module 2 is connected with speed feedback voltage sensor 7 connection, the incremental pulse generator module 4 is connected to the on-board controller 5 .

The specific content is as follows:

1) Application and development of incremental encoder: The selected incremental encoder has three signal outputs: A pulse, B pulse and Z pulse, using TTL level, A pulse is in front, B pulse is in the back, A , The difference between the B pulses is 90 degrees, and a Z pulse is sent out every circle, which can be used as a reference mechanical zero position. Use A ahead of B or B ahead of A to judge the direction. Incremental encoders are defined as clockwise rotation of the encoder when viewed from the shaft end, and A is 90° ahead of B, and vice versa. °;

2) Application and development of PLC AD analog conversion module: the range of selected speed voltage analog value is -10V to 10VDC (resolution: 5mV), and the allocation definition of 32 buffer memories (0~31) of AD module is as follows:

0#: channel initialization, default value H0000

1#---4#: The average sampling number of channel 1---channel 4 (1---4096), used to get the average result. The default value is set to 8 (normal speed), and 1 can be selected for high-speed operation.

5#---8#: The average input value of channel 1---channel 4 sampling number, that is, the average value of all samples is obtained according to the average sampling times specified in #1---#4.

9#---12#: The current value read from channel 1---channel 4.

13#, 14#: reserved, not defined.

15#: Select A/D conversion speed, set to 0 (default) to select normal speed (15ms/channel); set to 1 to select high speed (15ms/channel).

16#---19#: reserved, not defined.

20#: Reset to the default value and preset, the default value is 0.

21#: It is forbidden to adjust the offset and gain values. The default is (0, 1) to allow the state.

22#: offset, gain adjustment.

23#: offset value, the default value is 0.

24#: Gain value, the default value is 5000.

25#---28#: reserved, not defined.

29#: Error status.

30#: identification code K2010.

31#: disable.

3) Programming and development of CPU module: The PLC program must meet three requirements: namely, timing interrupt acquisition, analog input acquisition and pulse control output. The ladder diagram program of PLC is shown in Figure 3:

4) Timing interrupt acquisition: set the interrupt trigger time of timing interrupt I28 to 100ms, this method can ensure that the value of the analog input terminal is read cyclically;

5) PLC analog input: that is, A/D conversion, the conversion method has two methods: sampling processing and averaging processing:

Sampling processing: A/D conversion is performed on the analog input for each scan of the CPU module, digital output is performed every time and the value is stored in the digital output value, digital operation value, and analog input value monitoring.

Averaging processing: The digital output value is averaged for each channel, and the average value is stored in a special register. There are three types of average processing:

Time averaging: A/D conversion is performed according to the set time, the total value is averaged, and stored in the digital output value, digital operation value, and analog input value monitor. The number of processing times within the setting time varies depending on the scan time. Processing times = setting time/scanning time;

Count averaging: Averaging processing of A/D conversion values is specified by counting times, and the average values other than the maximum value and minimum value are digitally output, and stored in digital output value, digital operation value, and analog input value monitor. The time at which the average value based on the count average is stored in the digital output value, digital operation value, and analog input value monitor varies depending on the scan time. Processing time = setting times × scanning time;

Moving average: It is possible to specify the number of shift average processing of the A/D conversion value, digitally output the average value, and store it in the digital output value, digital operation value, and analog input value monitor.

6) Pulse output control: After the analog quantity processing module completes the A/D conversion and converts the analog quantity into a digital quantity, the positioning module is used to generate pulse output. First, you need to set the output port number and related parameters, and set the pulse output mode. Here we choose the PULSE/SIGN mode, as shown in Figure 4:

As shown in Figure 2, the workflow of the present invention comprises the following steps:

1) When the PLC is powered on, it enters the PLC internal self-inspection stage. At this stage, the PLC checks whether the hardware of the CPU module is normal, resets the watchdog timer, and completes some other internal work;

2) PLC program initialization stage, that is, the PLC loads the ladder diagram program and initializes all timers and registers;

3) When the train starts running, the incremental encoder tracks and collects the train wheel speed, and writes the speed and displacement information into the registers of the CPU module of the PLC according to the actual speed and displacement information;

4) After the train operation starts, if the train has a speed voltage output, the PLC analog acquisition module collects the speed voltage, and writes speed and displacement information to the register in the CPU module of the PLC;

5) In the PLC program processing stage, according to the steps of first up, then down, first left, then right, scan the ladder diagram program sentence by sentence and perform logical operations according to the results sampled into the input image register, and then store the operation results into the relevant image in the register;

6) According to the program instructions, the CPU module of the PLC converts the number of rotation cycles and the speed analog voltage collected per unit time into speed pulse information according to the PLC instructions;

7) The PLC allocates a new register, writes the result of the pulse number, and sends the pulse signal to the outside through the pulse sending module;

8) Regularly send out the result of the number of pulses per unit time, indicating the displacement increment information per unit time.

As shown in Figure 1, an incremental electronic coded odometer device based on PLC technology specifically includes an incremental encoder module, an AD conversion module, a PLC module, and an incremental pulse generator module.

Explanation of each module:

1. Incremental encoder:

Incremental encoder is a precision sensor that converts the mechanical rotation angle of the shaft into digital signal output by means of photoelectricity and other methods. Several light-transmitting sections and light-shielding sections are evenly distributed. The incremental encoder has no fixed initial zero point, and the output is a pulse proportional to the increment of the rotation angle, and a counter is needed to count the number of pulses. Every time a light-transmitting area is rotated, a pulse signal is sent, the current value of the counter is increased by 1, and the counting result corresponds to the increment of the rotation angle.

In addition to the two pairs of photocouplers of the dual-channel incremental encoder inside the selected three-channel incremental encoder, there is a light-transmitting section in the other channel of the pulse code disc, which outputs 1 for each revolution. A pulse, which is called the Z-phase zero pulse, is used as the system zero clearing signal, or the origin of the coordinates, to reduce the cumulative error of measurement. If the period of the encoder output pulse is greater than twice the scan cycle time of the PLC, by judging the 0 and 1 states of the A-phase pulse signal on the rising edge of the B-phase pulse, the direction of the encoder rotation can be judged.

2. AD conversion module:

The FX2N-4AD analog special module has four input channels. The input channel receives an analog signal and converts it into a digital quantity, which is called A/D conversion. The maximum resolution of FX2N-4AD is 12 bits. The selection of input/output based on voltage or current is done through user wiring, and the available analog value ranges are -10V to 10VDC (resolution 5mV), and/or 4 to 20mA, -20 to 20mA (resolution: 20μA ). FX2N-4AD and FX2N main unit exchange data through buffer memories. FX2N-4AD has a total of 32 buffer memories (16 bits each). FX2N-4AD occupies 8 points of the FX2N expansion bus line. These 8 points can be allocated as Input or output. The FX2N-4AD consumes 30mA from the 5V power supply of the FX2N main unit and active expansion unit.

3. CPU module of PLC:

The CPU consists of a controller, arithmetic unit and registers. These circuits are integrated on one chip. The CPU is connected with the I/O interface circuit through the address bus and the data bus.

The CPU module is used to store and execute the PLC ladder diagram program, and perform calculation and execution according to the user's ladder diagram instructions. When the program input from the programmer is stored in the user program memory, then the CPU translates the user program into a user compiled program recognized by the PLC according to the function given by the system (interpretation and compilation of the system program memory). The input state and input information are input from the input interface, and the CPU stores them in the working data memory or the input image register. Then the data and the program are organically combined by the CPU. Store the result in the output image register or working data memory, and then output to the output interface to control the external driver.

4. Pulse generator module:

Use the high-frequency output of the transistor IO of the PLC, and add a power supply to generate a digital pulse waveform. In the first scan cycle of the PLC, the M1 normally closed contact is closed, so the M1 coil can be energized; in the second scan cycle, because the M1 coil has been energized in the previous scan cycle, the normally closed contact of M1 is disconnected , thus de-energizing the M1 coil. Therefore, the electrification time of the Ml coil is one scan cycle. The M1 coil is continuously energized and de-energized, and its normally open contacts are also continuously closed and disconnected, which produces a continuous pulse signal output with a pulse width of one scanning period, which is suitable for use with trams. Acquisition of speed signals.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of various equivalents within the technical scope disclosed in the present invention. Modifications or replacements shall all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (8)

1. The utility model provides an incremental electronic coding odometer device based on PLC technique, the device is installed on the tram, its characterized in that, odometer device respectively with tram's wheel rotational speed sensor, speed feedback voltage sensor and on-vehicle controller be connected, odometer device include incremental encoder module, AD conversion module, PLC module, incremental pulse generator module, the PLC module respectively with incremental encoder module, AD conversion module, incremental pulse generator module connection, incremental encoder module be connected with wheel rotational speed sensor, AD conversion module be connected with speed feedback voltage sensor, incremental pulse generator module be connected with on-vehicle controller.

2. The incremental electronic coded odometer device based on PLC technology according to claim 1, wherein the incremental encoder module is a three-channel incremental encoder provided with three signal outputs, respectively: pulse A, pulse B and pulse Z, wherein pulse A is before pulse B is after pulse A, pulse A and pulse B differ by 90 degrees, each circle sends out a pulse Z, as the reference mechanical zero position; the encoder rotates clockwise as seen at the shaft end, namely the A pulse leads the B pulse by 90 degrees, and rotates counter-clockwise as seen at the shaft end, namely the B pulse leads the A pulse by 90 degrees.

3. The incremental electronic code odometer device based on PLC technology according to claim 1, wherein the AD conversion module is provided with four input channels and 32 buffers, wherein the four input channels are used for receiving analog signals and converting them into digital quantities, and the 32 buffers are allocated as follows:

0#: channel initialization, default value H0000;

1# -4#: channel 1- -the average number of samples of channel 4, used to obtain the average result;

5# -8# -average input value of channel 1-channel 4 samples, i.e. average sampling number according to the number of times # 1-4, to obtain average value of all samples;

9-12 #: channel 1-channel 4 reads in the current value;

13#,14#: reserving and not defining;

15#: selecting an A/D conversion speed, and selecting a normal speed if the A/D conversion speed is set to 0; setting 1, selecting a high speed, wherein the speed is 15 ms/channel;

16-19 #: reserving and not defining;

20#: resetting to a default value and presetting, wherein the default value is 0;

21#: inhibiting the offset and gain values from being adjusted;

22#: offset, gain adjustment;

23#: offset value, default value is 0;

24#: gain value, default value is 5000;

25# -28#: reserving and not defining;

29#: an error condition;

30#: an identification code K2010;

31#: disabling.

4. The incremental electronic coded odometer device based on PLC technology according to claim 1, wherein the PLC module comprises a CPU module comprising the following functions: the acquisition is interrupted regularly, the analog quantity is input and acquired, and the pulse control output is carried out.

5. The incremental electronic code odometer device based on PLC technology according to claim 4, wherein the analog input acquisition includes a sampling process and an averaging process;

the sampling process specifically comprises the following steps: performing A/D conversion on the analog input according to each scan of the CPU module, performing digital output each time, and storing the values into digital output values, digital operation values and analog input value monitoring;

the average treatment is specifically as follows: the digital output values are averaged for each channel and the average value is stored in a setting register.

6. The incremental electronic coded odometer device based on PLC technology according to claim 5, wherein the averaging process is three, respectively:

time average: performing A/D conversion according to the set time, averaging the combined value, and storing the average value in digital output value, digital operation value and analog input value monitoring; the number of processes within a set time varies depending on the scan time, where the number of processes = set time/scan time;

the times average: designating average processing of A/D conversion values by times, digitally outputting average values except maximum and minimum values, and storing in digital output value, digital operation value and analog input value monitoring; the time for which the average value based on the number average is stored in the digital output value, the digital operation value, and the analog input value monitoring varies depending on the scanning time; processing time = set number x scan time;

moving average: the number of times of shift average processing of the A/D conversion value is specified, and the average value is digitally outputted and stored in digital output value, digital operation value and analog input value monitoring.

7. The incremental electronic code odometer device based on PLC technology according to claim 4, wherein the pulse control output is specifically: firstly, setting an output port number and parameters, setting a PULSE output mode, and selecting a PULSE/SIGN mode to perform PULSE output.

8. Use of an incremental electronic coded odometer device based on PLC technology according to claim 1, characterised in that it comprises the following steps:

1) After the PLC module is powered on, entering an internal self-checking stage of the PLC module, wherein the stage comprises the steps of checking whether hardware of the CPU module is normal or not by the PLC module and resetting a monitoring timer;

2) Initializing a PLC module, namely loading a ladder diagram program by the PLC module, and initializing all timers and registers;

3) After the train is started, the incremental encoder module tracks and collects the rotation speed of the train wheels, and writes speed and displacement information into a register in a CPU module of the PLC module according to the actual rotation speed and displacement information;

4) After the train is started, if the train has speed voltage output, the AD conversion module collects the speed voltage and writes speed and displacement information into a register in a CPU module of the PLC module;

5) The PLC module processing stage, according to the steps of up and down and left and right, scanning the ladder diagram program sentence by sentence, and according to the result sampled into the input mapping register, making logic operation, and storing the operation result into the related mapping register;

6) The CPU module of the PLC module converts the rotation cycle number and the speed analog voltage acquired in unit time into speed pulse information according to the PLC instruction;

7) The PLC allocates a new register, writes a pulse number result, and externally sends a pulse signal through an incremental pulse generator module;

8) The pulse number result in the unit time is sent out periodically to represent the displacement increment information in the unit time.

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