CN106132000B - A kind of digital radio LED light source controller - Google Patents

Abstract

The invention relates to machine vision light source control for industrial product surface quality detection, in particular to a digital wireless LED light source controller, including a hardware part and a software part. The hardware part includes host computer, wireless serial port communication module, embedded control unit, light source drive circuit, LED light source, display module and power supply module; the software part includes host computer software, embedded control unit program and LED gray value adjustment algorithm . The operator uses the host computer software to send instructions to the embedded control unit, and the embedded control unit outputs a PWM wave with a corresponding duty cycle after receiving the instruction to process the data, thereby controlling the brightness of the LED light source. The invention has low heat generation, reasonable structure, and can accurately and stably control LED light sources of four channels at the same time. In particular, the control command data adopts non-contact wireless input, which saves the difficulty of wiring and is simpler in the actual installation and use process.

Description

A digital wireless LED light source controller

technical field

The invention relates to machine vision light source control for industrial product surface quality detection, in particular to a digital wireless LED light source controller.

Background technique

Machine vision system is a system that uses machines instead of human eyes to obtain images of objective things, and processes, analyzes and recognizes the acquired images through computer and image processing technology, including lighting, lenses, cameras, image acquisition cards and visual processors. , each part may affect the result of image processing, and even lead to the instability of the machine vision system. Among them, the light source controller is one of the most critical links.

The existing light source controller has the problems of obvious heat generation and troublesome wiring between the control instruction input module and the controller. In the industrial field, due to the limitation of the installation environment, it is sometimes necessary to install the control signal input module for adjusting the brightness of the light source separately from other modules of the light source controller.

Contents of the invention

The present invention proposes a digital wireless LED light source controller in order to solve the problems that the existing light source controller generates heat obviously and the wiring between the control command input module and the controller is troublesome when it is applied in the industrial field.

A digital wireless LED light source controller, including a software part and a hardware part; the hardware part includes a host computer, a wireless serial port communication module, an embedded control unit, a light source driving circuit, an LED light source, a display module and a power supply module; the The upper computer is bidirectionally connected with the embedded control unit through the wireless serial port communication module for sending instructions and receiving data; the embedded control unit is connected with the LED light source through the light source driving circuit, and uses PWM control technology to adjust the brightness of the LED light source; The display module is composed of a digital tube display circuit, connected with the embedded control unit, and used to display the channel number and the brightness value of the LED light source; the power supply module is connected with the wireless serial communication module, the embedded control unit, and the light source drive circuit respectively. , Display module connection, provide stable power supply;

The software part includes host computer software, an embedded control unit program and an LED gray value adjustment algorithm; the host computer software is used to select the LED light source channel and send a control command for adjusting the brightness of the LED light source; the embedded control unit program It is used to analyze and process the received control command, and then adjust the duty cycle of the PWM wave according to the processing result, thereby adjusting the brightness of the LED light source; the LED gray value adjustment algorithm is to use the gray value of the LED light source and the PWM duty cycle The relationship between the duty ratio, the adjustment of the gray value of the LED light source can be realized by dividing the multi-level duty ratio by the spacing;

The embedded control unit adopts the LPC2148 chip as the core control chip, and the LED gray value adjustment algorithm includes the following steps:

S1 sets the PWM wave to be controlled by a single edge. It is high at the beginning of the PWM cycle, and the cycle of each PWM is constant. The cycle size is given by the following formula:

f _cclk represents the system clock frequency of the LPC2148 chip, n represents the value of the PWMMR0 register of the core control chip LPC2148, and T _PWM represents the cycle of each PWM;

S2 digitizes the cycle of the PWM wave into 256 parts, and controls the high level time in each PWM cycle by setting the PWM matching register of the core control chip LPC2148. In the embedded control unit program, the value of the PWM matching register is given by the following formula out:

i=1,2,3,4,5,6; N=0,1,2,3...255; N represents the gray value of the LED light source, PWMMR _i represents the value of the PWM matching register;

S3 achieves a spacing of 0-255 level duty cycle adjustment, so as to realize the adjustment of the gray value of the LED light source from 0-255, the duty cycle of the PWM wave is:

DutyRatio represents the duty cycle.

Further, the hardware part also includes an infrared control module. The infrared control module is divided into an infrared remote control button and an infrared receiving circuit. The infrared receiving circuit is connected to the embedded control unit. The infrared remote control button is used to send instructions, and the infrared receiving circuit It is used to receive instructions and send them to the embedded control unit. In addition to sending commands to the embedded control unit through the wireless remote control of the host computer, the operator can also use the infrared control module to remotely send commands, support multiple modes of sending commands, and save the trouble of wiring.

Further, the host computer software includes four parts: interface initialization, serial port initialization, LED light source channel selection and control instruction sending.

Further, the embedded control unit program includes four parts: device initialization, detecting control instructions, analyzing control instructions and adjusting PWM wave duty cycle, and device initialization includes I/O port initialization, phase-locked loop initialization, and infrared pin initialization , serial port initialization and pulse width modulation initialization.

Further, there are four LED light sources, and the light source drive circuit includes a four-channel drive circuit for providing power supply voltages for the four LED light sources.

Further, the wireless serial port communication module is divided into an upper computer wireless serial port module and a lower computer wireless serial port module, the upper computer wireless serial port module is bidirectionally connected to the upper computer, and the lower computer wireless serial port module is connected to the serial port of the embedded control unit. Two-way connection, so as to realize the two-way communication of data between the host computer and the embedded control unit.

Further, the embedded control unit adopts the LPC2148 chip as the core control chip, and the frequency of the PWM wave output by it can reach the order of 10 ⁵ at most. The embedded control unit uses LPC2148 as the core control chip, which is used to analyze and process the control commands sent by the upper computer through the wireless serial port module and the control commands sent by the operator through the infrared remote control button to adjust the brightness of the LED light source, and output the corresponding duty cycle according to the analysis and processing results. The PWM wave of the ratio can adjust the brightness of the LED light source; at the same time, the embedded control unit can control the display module to display the channel number and the brightness value of the LED light source. In addition, the embedded control unit can independently output four channels of PWM waves with different duty ratios at the same time, and can adjust the duty ratios of each PWM wave in real time, so as to achieve the purpose of independently adjusting the brightness of the four LED light sources in real time. Since the brightness of the LED light source is adjusted by using PWM control technology, the heat generation of the light source controller is not obvious. In addition, the frequency of the PWM wave can be as high as 10 ⁵ orders of magnitude, which is enough to accurately and stably control the brightness of the LED light source, so there is basically no stroboscopic phenomenon in the process of image acquisition.

Further, the light source driving circuit includes a high frequency switching circuit.

Compared with the prior art, the present invention has a reasonable structure, can independently, accurately and stably control the LED light source of four channels at the same time, adopts PWM control technology to adjust the brightness of the LED light source, and has a small calorific value; and because it adopts a non-contact method (wireless Serial port communication and infrared remote control) to input control instruction data, which overcomes the complexity of the wiring process and is not limited by the installation environment. Therefore, it is more flexible in the installation and use of industrial inspection.

Description of drawings

Fig. 1 is a schematic diagram of hardware structure of the present invention;

Fig. 2 is a flow chart of upper computer software of the present invention;

Fig. 3 is the upper computer software interface figure of the present invention;

Fig. 4 is a program flow chart of the embedded control unit of the present invention.

Detailed ways

The present invention proposes a digital wireless light source controller, and the specific implementation will be described below with reference to the accompanying drawings.

The present invention includes a hardware part and a software part. As shown in FIG. 1, the hardware part includes a host computer, a wireless serial port communication module, an infrared control module, an embedded control unit, a light source driving circuit, a four-way LED light source, and a display module. and power supply module.

The wireless serial port communication module is divided into the upper computer wireless serial port module and the lower computer wireless serial port module. Two-way communication of data between the host computer and the embedded control unit;

The infrared control module is divided into an infrared remote control button and an infrared receiving circuit, the infrared receiving circuit is connected with the embedded control unit, the infrared remote control button is used to send instructions, and the infrared receiving circuit is used to receive instructions and send them to the embedded control unit;

The embedded control unit adopts the LPC2148 chip as the core control chip, and the frequency of the PWM wave output by it is up to 10 ⁵ orders of magnitude; the PWM wave output interface of the embedded control unit is connected to the input port of the light source driving circuit;

The light source drive circuit is composed of a high-frequency switch circuit and a drive circuit, and is used to provide the power supply voltage of the four-way LED light source, and its output terminal is connected to the receiving end of the four-way LED light source;

At the same time, the embedded control unit is also connected to the display module in one direction to control it to display the channel number and the brightness value of the LED light source;

The power receiving end of the power supply module is connected to the external power supply, and the power supply end is simultaneously connected to the power receiving end of the display module, the power receiving end of the embedded control unit, the power receiving end of the light source driving circuit and the power receiving end of the wireless serial communication module , to provide the required voltage for these modules to ensure their normal operation.

The software part of the invention includes upper computer software, embedded control unit program and LED gray value adjustment algorithm. The host computer software is used to select the channel of the LED light source, and sends a control command to adjust the brightness of the LED light source; the embedded control unit program is used to analyze and process the received control command, and then adjust the duty of the PWM wave according to the processing result ratio, thereby adjusting the brightness of the LED light source; the LED gray value adjustment algorithm is to use the relationship between the LED light source gray value and the PWM duty cycle, and the LED light source gray value can be realized by dividing the multi-level duty cycle adjustment by spacing. degree value adjustment.

As shown in Figure 2, the upper computer software includes four parts: interface initialization, serial port initialization, selection of LED light source channel and sending control orders. First, initialize the software interface and the serial port. After the initialization is completed, determine whether the serial port has been opened. If it is not open, re-initialize the serial port; if the serial port is already open, select the channel number of the LED light source and send the control command to adjust the brightness of the LED light source.

As shown in Figure 3, the interface of the host computer software includes LED light source gray value manual input column 1, LED light source gray value sliding input column 2, LED light source channel selection column 3, sending data 4, serial port switch 5, and status column 6 and baud rate selection column 7. The operator first selects the baud rate of the serial port communication through the baud rate selection column 7, opens the serial port of the upper computer through the serial port switch 5, and then selects the channel of the LED light source through the LED light source channel selection column 3, and then manually selects the channel through the gray value of the LED light source. Input column 1 or enter the gray value of the LED light source by sliding the slider up and down, and finally click Send Data 4, so that the data can be sent. In addition, the operator can get the status of the host computer serial port and the serial number of the LED light source channel from the status bar 6 .

As shown in Figure 4, the embedded control unit program includes initialization (I/O port initialization, phase-locked loop initialization, infrared pin initialization, serial port initialization and pulse width modulation initialization), detection control instructions, analysis control instructions and PWM wave adjustment The duty cycle has four parts. First, initialize the I/O port, phase-locked loop, infrared pin, serial port and pulse width modulation of the embedded control unit, and then detect whether the serial port and infrared pin have control command input. If the input of the control command is not detected, continue to detect whether there is a control command input; if the input of the control command is detected, the control command is decoded and analyzed, and finally the duty cycle of the PWM wave is adjusted according to the analysis result.

The implementation steps of the corresponding LED gray value adjustment algorithm are as follows:

S1 sets the PWM wave as single edge control, all high level at the beginning of the PWM cycle, and the cycle of each PWM is constant, the present invention sets the PWMMR0 register of the core control chip LPC2148 of the embedded control unit to be 256, thereby The period of the output PWM wave is 256 system clock periods, and its size is given by the following formula:

f _cclk represents the LPC2148 system clock frequency, n=256, T _PWM represents the period of each PWM;

S2 digitizes the cycle of the PWM wave into 256 parts, and controls the high level time in each PWM cycle by setting the PWM matching register of the core control chip LPC2148. In the embedded control unit program, set the PWMR2, PWMMR4, PWMMR5, PWMMR6 value to control the duty cycle of the four PWM waves. The values of PWMMR2, PWMMR4, PWMMR5, PWMMR6 are given by the following formulas:

i=1,2,3,4,5,6; N=0,1,2,3...255. N represents the gray value of the LED light source, and PWMMR _i represents the value of the PWM matching register;

S3 achieves a spacing of 0-255 level duty cycle adjustment, so as to realize the adjustment of the gray value of the LED light source from 0-255. The duty cycle of the PWM wave is:

DutyRatio represents the duty cycle;

The above formula shows the relationship between the gray value of the LED light source and the PWM duty cycle, and the passing distance is The 0-255 duty ratio adjustment can realize the adjustment of the gray value of the LED light source from 0-255.

The operator can send control commands to adjust the brightness of the LED light source through the host computer software. These control commands are sent through the wireless serial port module of the host computer bidirectionally connected with the host computer. When the wireless serial port module of the lower computer bidirectionally connected with the embedded control unit receives these After the control command is sent to the embedded control unit through the URAT port. After the embedded control unit receives the control command to adjust the brightness of the LED light source, it analyzes and processes the embedded control unit program, and then makes a corresponding response, that is, outputs a PWM wave with a corresponding duty cycle to the light source driving circuit, thereby adjusting the LED light source. The brightness of the light source. In addition, the operator can also send a control command to adjust the brightness of the LED light source through the infrared remote control button, and the infrared receiving circuit is responsible for receiving the control command sent by the infrared remote control button and sending it to the embedded control unit. After the embedded control unit program decodes, analyzes and processes the received control instructions, it outputs PWM waves with corresponding duty ratios to the light source drive circuit, and then controls the brightness of the LED light source.

The invention adopts a non-contact way to input control instruction data, overcomes the complexity of the wiring process, is not limited by the installation environment, and is more flexible in the installation and use process of industrial detection.

Claims (8)

1. A digital wireless LED light source controller, characterized in that it comprises a software part and a hardware part; The hardware part includes an upper computer, a wireless serial communication module, an embedded control unit, a light source driving circuit, an LED light source, a display module and a power supply module; the upper computer is bidirectionally connected with the embedded control unit through the wireless serial communication module, For sending instructions and receiving data; the embedded control unit is connected with the LED light source through the light source driving circuit, and uses PWM control technology to adjust the brightness of the LED light source; the display module is composed of a digital tube display circuit, connected with the embedded control unit, It is used to display the channel number and the brightness value of the LED light source; the power supply module is respectively connected with the wireless serial communication module, the embedded control unit, the light source driving circuit, and the display module to provide a stable power supply; The software part includes host computer software, an embedded control unit program and an LED gray value adjustment algorithm; the host computer software is used to select the LED light source channel and send a control command for adjusting the brightness of the LED light source; the embedded control unit program It is used to analyze and process the received control command, and then adjust the duty cycle of the PWM wave according to the processing result, thereby adjusting the brightness of the LED light source; the LED gray value adjustment algorithm is to use the gray value of the LED light source and the PWM duty cycle The relationship between the duty ratio, the adjustment of the gray value of the LED light source can be realized by dividing the multi-level duty ratio by the spacing; The embedded control unit adopts the LPC2148 chip as the core control chip, and the LED gray value adjustment algorithm includes the following steps: S1 sets the PWM wave to be controlled by a single edge. It is high at the beginning of the PWM cycle, and the cycle of each PWM is constant. The cycle size is given by the following formula: <mrow><msub><mi>T</mi><mrow><mi>P</mi><mi>W</mi><mi>M</mi></mrow></msub><mo>=</mo><mi>n</mi><mo>&amp;times;</mo><mfrac><mn>1</mn><msub><mi>f</mi><mrow><mi>c</mi><mi>c</mi><mi>l</mi><mi>k</mi></mrow></msub></mfrac></mrow> f _cclk represents the system clock frequency of the LPC2148 chip, n represents the value of the PWMMR0 register of the core control chip LPC2148, and T _PWM represents the cycle of each PWM; S2 digitizes the cycle of the PWM wave into 256 parts, and controls the high level time in each PWM cycle by setting the PWM matching register of the core control chip LPC2148. In the embedded control unit program, the value of the PWM matching register is given by the following formula out: <mrow><msub><mi>PWMMR</mi><mi>i</mi></msub><mo>=</mo><mfrac><mrow><mi>P</mi><mi>W</mi><mi>M</mi><mi>M</mi><mi>R</mi><mn>0</mn></mrow><mn>256</mn></mfrac><mo>&amp;times;</mo><mi>N</mi></mrow> i=1,2,3,4,5,6; N=0,1,2,3...255, N represents the gray value of the LED light source, PWMMR _i represents the value of the PWM matching register; S3 achieves a spacing of 0-255 level duty cycle adjustment, so as to realize the adjustment of the gray value of the LED light source from 0-255, the duty cycle of the PWM wave is: <mrow><mi>D</mi><mi>u</mi><mi>t</mi><mi>y</mi><mi>R</mi><mi>a</mi>><mi>t</mi><mi>i</mi><mi>o</mi><mo>=</mo><mfrac><mrow><msub><mi>PWMMR</mi><mi>i</mi></msub></mrow><mrow><mi>P</mi><mi>W</mi><mi>M</mi><mi>M</mi><mi>R</mi><mn>0</mn></mrow></mfrac><mo>=</mo><mfrac><mi>N</mi><mn>256</mn></mfrac></mrow> DutyRatio represents the duty cycle. 2. The light source controller according to claim 1, wherein the hardware part also includes an infrared control module, the infrared control module is divided into an infrared remote control button and an infrared receiving circuit, and the infrared receiving circuit and the embedded control unit connection, the infrared remote control button is used to send instructions, and the infrared receiving circuit is used to receive instructions and send them to the embedded control unit. 3. The light source controller according to claim 1, wherein the host computer software includes four parts: interface initialization, serial port initialization, LED light source channel selection and control instruction sending. 4. light source controller according to claim 1, is characterized in that, described embedded control unit program comprises device initialization, detects control instruction, resolves control instruction and regulates four parts of PWM wave duty cycle, and device initialization comprises I /O port initialization, PLL initialization, infrared pin initialization, serial port initialization and pulse width modulation initialization. 5 . The light source controller according to claim 1 , wherein the LED light source has four channels, and the light source driving circuit includes a four-channel driving circuit. 6. The light source controller according to claim 1, wherein the wireless serial port communication module is divided into an upper computer wireless serial port module and a lower computer wireless serial port module, and the upper computer wireless serial port module and the upper computer are bidirectionally connected, The wireless serial port module of the lower computer is bidirectionally connected with the serial port of the embedded control unit, so as to realize the bidirectional communication of data between the upper computer and the embedded control unit. 7 . The light source controller according to claim 1 , wherein the embedded control unit uses an LPC2148 chip as the core control chip, and the frequency of the PWM wave output by it is up to an order of magnitude of 10 ⁵ . 8. The light source controller according to claim 1, wherein the light source driving circuit comprises a high frequency switching circuit.