Transcription of VB與PLC通訊控制 - web.ncyu.edu.tw
1 NCYU_BME1VB PLC NCYU_BME2 NCYU_BME3 NCYU_BME4 Visual Basic RS232 PLC PLC NCYU_BME5 NCYU_BME6 NCYU_BME7 NCYU_BME8 NCYU_BME9 NCYU_BME10 NCYU_BME11 PLC NCYU_BME12 1:CD Carrier Detect ( )2:RXD Receive3:TXD Transmit4:DTR Data Terminal Ready ( )5:GND Ground6:DSR Data Set Ready ( )7:RTS Request To Send ( )8:CTS Clear To Send ( )9:RI Ring Indicator ( )1 2 3456789123456789RS-232 NCYU_BME13 2 (RXD)3 (TXD)5 (GND)4 (DTR)1 (DCD)6 (DSR)7 (RTS) 8 (CTS)9 (RI) 9 Pin9 Pin3 (TXD)2 (RXD)5 (GND)6 (DSR)1 (DCD)4 (DTR)8 (CTS)7 (RTS) 9 (RI) NCYU_BME14 COM Port (1) Baud Rate Parity 1 Data Bits 7 8 Stop Bits 1 2 bits NCYU_BME15zBaud RateUnit: bits per second (bps)1200, 2400, 4800, 9600, 19200, 38400.
2 Baud rate = Data transfer rate ?zData bits7 bits: ASCII Code 0~127, Text Data ( )8 bits: ASCII Code 0~255, Binary Data( )COM Port (2)0 0 0 1 1 1 1 0 1 10 0 1 1 1 NCYU_BME16 Parity( ): bit 1 NoneEven: Odd: A01000001 010000010 01000001 010000011 COM Port (3)NCYU_BME17 Start Bits 1 bitsStop Bits 1 or 2 bits Ex: Data Bits:8, Stop bits:1, No Parity Start+Data+Parity+End1 0 1 0 0 1 0 0 1 1 Data (Hex: 91)StopBitStartBitStopBitStartBitCOM Port (4)NCYU_BME18VB 1. Imports Dim RS232 As SerialPort SerialPort NCYU_BME19 SerialPort a. b. c. d. NCYU_BME20 PropertiesBaudRate, DataBits, HandshakeParity, PortName, ReadBufferSizeStopBits, ReceiveBytesThresholdSerialPort NCYU_BME21 SerialPort Property = COM1 => use Com1 = 1200, 2400, 4800, 9600, 19200.
3 ( , , , ) = = (None, OnePointFive, Two)NCYU_BME22 Open Close <= Open Com <= <= <= Close Com PortReadExistingEx:InStr = <= ( AT & vbCrLf )=> AT & Return SerialPort EventsNCYU_BME23 SerialPort SerialPort HandShakingt BaudRate ReadExisting Write FX-2N 9600 bps 7 1 NCYU_BME25 PLC PLC PLC NCYU_BME26 PLC 1. 2. NCYU_BME27 PLC Chr(2)Chr(3) 1 Chr(2)Chr(3) 0 01 01 NCYU_BME28FX-2N NCYU_BME298-15 NCYU_BME30 ( ) Y 53Y0-Y7 2 14 CheckSum(ByVal InputStr As String) As StringDim StrLen As Integer, a As Integer, j As IntegerDim StrCh As String, Sum As StringStrLen = = 0 For j = 1 To StrLenStrCh = Mid(InputStr, j, 1)a = Asc(StrCh) + aNext jSum = Hex(a)If = 1 Then Sum = "0" + SumCheckSum = Mid(Sum, - 1, 2)End FunctionCheckSum 2 NCYU_BME32 ACK (ASCII 6) NAK (ASCII 21)NCYU_BME33 X0-X7 5C Chr(3) 01 0080 0 Chr(2)CheckSum 6C Chr(3) 63 Chr(2)CheckSum 6 543 512+54+51+3=110110 6C( ) X0-X7 11000110X0X1X2X3X4X5X6X7 1 2&3 4 5&6 NCYU_BME34 PLC (OutCmd)' TimeDelay(100)
4 ' RetStr = ()' PLC 9 PLC 40 Private Sub TimeDelay(ByVal DT As Integer, ByVal retlen As Integer)Dim StartTick As IntegerStartTick = () ' TickDoIf >= retlen Then Exit SubIf () - StartTick >= DT Then Exit () ' LoopEnd SubRetlen retlen=1 retlen=?NCYU_BME35 NCYU_BME36XY Y
