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POHow to send command to serial port (JAVA + RXTX)
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copied!<p>I have a problem with sending data input to a weight balance. I need to send a <code>ESC P CR LF</code> command. I use the RXTX lib. I dont know why it does not work. Below is the code.</p> <pre><code>public static class SerialWriter implements Runnable { OutputStream out; public SerialWriter ( OutputStream out ) { this.out = out; } public void run () { try { while ( true ) { this.out.write(new byte[]{0x1B, 0x50, 0x0D, 0x0A}); Thread.sleep(1000); } } catch ( IOException | InterruptedException e ) { e.printStackTrace(); } } } </code></pre> <p>I tried with <code>flush</code> but nothing happened. I attached full (modified) code below. </p> <pre><code>package model; import gnu.io.CommPort; import gnu.io.CommPortIdentifier; import gnu.io.SerialPort; import java.io.FileDescriptor; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class FirstSteps { public FirstSteps() { super(); } void connect ( String portName ) throws Exception { CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName); if ( portIdentifier.isCurrentlyOwned() ) { System.out.println("Error: Port is currently in use"); } else { System.out.println("Connect 1/2"); CommPort commPort = portIdentifier.open(this.getClass().getName(),6000); if ( commPort instanceof SerialPort ) { System.out.println("Connect 2/2"); SerialPort serialPort = (SerialPort) commPort; System.out.println("BaudRate: " + serialPort.getBaudRate()); System.out.println("DataBIts: " + serialPort.getDataBits()); System.out.println("StopBits: " + serialPort.getStopBits()); System.out.println("Parity: " + serialPort.getParity()); System.out.println("FlowControl: " + serialPort.getFlowControlMode()); serialPort.setSerialPortParams(4800,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_ODD); serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_RTSCTS_IN); System.out.println("BaudRate: " + serialPort.getBaudRate()); System.out.println("DataBIts: " + serialPort.getDataBits()); System.out.println("StopBits: " + serialPort.getStopBits()); System.out.println("Parity: " + serialPort.getParity()); System.out.println("FlowControl: " + serialPort.getFlowControlMode()); InputStream in = serialPort.getInputStream(); OutputStream out = serialPort.getOutputStream(); (new Thread(new SerialReader(in))).start(); (new Thread(new SerialWriter(out))).start(); } else { System.out.println("Error: Only serial ports are handled by this example."); } } } /** */ public static class SerialReader implements Runnable { InputStream in; public SerialReader ( InputStream in ) { this.in = in; } public void run () { byte[] buffer = new byte[1024]; int len = -1; try { while ( ( len = this.in.read(buffer)) > -1 ) { //System.out.println("Received a signal."); System.out.print(new String(buffer,0,len)); } } catch ( IOException e ) { e.printStackTrace(); } } } /** */ public static class SerialWriter implements Runnable { OutputStream out; public SerialWriter ( OutputStream out ) { this.out = out; } public void run () { try { byte[] array = {0x1B, 0x50, 0x0D, 0x0A}; while ( true ) { this.out.write(new byte[]{0x1B, 0x50, 0x0D, 0x0A}); this.out.flush(); Thread.sleep(1000); } } catch ( IOException | InterruptedException e ) { e.printStackTrace(); } } } public static void main ( String[] args ) { try { (new FirstSteps()).connect("COM7"); } catch ( Exception e ) { // TODO Auto-generated catch block e.printStackTrace(); } } } </code></pre>

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