The communication format of the computer and PLC and implementation method

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1 foreword but program controller (PLC) has opening of a process designing. The PLC that with Japan company of 3 water chestnut produces is exemple (include FX series and A series) , mouth of its process designing is RS-422 format, differ to be divided again according to PLC model for 8 needles process designing mouth and 25 needles process designing mouth. To latter, but direct SC, cable of 08 process designing mixes the process designing mouth of PLC the RS of the microcomputer, 232 join rise; To latter, the 8 stitches that still need to change cable general PLC process designing mouth and cable of 25 needles process designing are linked together. No matter why be planted circumstance, once conduct PLC user program area of PLC user program by environment of microcomputer process designing, mouth of its process designing is done not have mostly by recycle. Actually, this is a kind of waste. That is to say, can use a cause for gossip of this process designing to show the data news report of microcomputer and PLC, under management of the in a subtle way of working state offer PLC computer. Type of command of operation of mouth of 2 process designing and communication port initialization are serial communication is a kind of when news report has between the computer and other machine commonly used method, the API function that realizes all sorts of serial communication was provided in WINDOWS operating system. Pass SC, cable of 08 process designing or FX232AW module, but the RS of serial communication mouth the microcomputer, the join of 232 process designing mouth with PLC rise, such microcomputers can are opposite the RAM area data of PLC undertakes reading, keep an operation. Have some character by PLC itself place, can undertake to PLC the following the operation of 4 kinds of types: (1) component or word component condition read an operation (CMD0) ; (2) component or word component condition keep an operation (CMD1) ; (3) compulsive ON operates cell (CMD7) ; (4) compulsive OFF operates cell (CMD8) . Additional, having 4 kinds of afore-mentioned operations previously, want to undertake to port initialization is operated above all, namely set communication agreement (include to install digit of communication baud rate, data, data to stop reach) of odd even desired result. DCB of a structure was defined in the SDK of WINDOWS, how does palpability of this structure circumstantiate undertake controlling to communication port, so the initialization of communication port also undertakes for the center around the move proper setting to this structure. Language of ＋ of the ＋ that use VC realizes port initialization to be as follows: BOOL CSerial: 　 of Open(int NPort){　 / / NPort is a microcomputer date of port of serial communication mouth. Nport=1 is port 1; NPort=2 is port 2. M_hIDComDev=CreateFile(szPort of 　 of DCB Dob; 　 of 　 of Char SzPort[15]; 　 , GENERIC_READ │ GENERIC_WRITE, o, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL │ FILE_FLAG_OVERLAPPED, dcb of NULL); 　 　 .

GetCommState(m_hIDComDev of DCB1ength=sizeof(DCB); 　 　 , &dcb);// obtains communication resource to install 　 Dcb currently.

Rate of BaudRate=9600;// set baud is Dcb of 9600 　 　 .

ByteSize=7;//7 data 　 Dcb.

Parity=2;// occasionally Dcb of desired result 　 .

StopBits=0;// set stops a 　 If(SetCommState(m_hIDComDev 1 times, else Return(FALSE);// of &dcb)return(TRUE); 　 　 installs port, if install a success to return TRUE, what return FALSE ｝ 　 to need to explain otherwise is CSerial be be used at serial communication kind, it included the needs function that has serial news report. Outside dividing Open of afore-mentioned function of port initialization member, still include additional function of two important members: One is EndData, transmit data to serial port from a buffer. Another is ReadData, the reception from port reads in data in buffer. Next, 4 kinds of afore-mentioned operations have in every before a kind of medium operation, have handclasp contact even. To PLC code of ENQ(of mark of hair request question is OX05) , the response that reads PLC next question mark. The response that if read,arrives question mark is OX06) for ACK(code, express PLC already be all set, wait to receive communication data. Language of ＋ of ＋ of handclasp contact VC shows PLC already be all set, wait to receive communication data. Implementation of language of ＋ of ＋ of handclasp contact VC is: BOOL CNTJD1g: ReadFromPLC(char *Read_char Char *Read_address, if(Serial of kind of 　 of 　 of 　 Char Read_BUFFER; that CSerial Serial;// of 　 of Int Read_bytes){　 uses at serial communication.

Open(2)// initialization is serial Serial of 　 of {of 　 of 　 of COM2 of buccal communication mouth.

SendData(&ENQ_request, 1);// sends Sleep(1000);// of 　 of 　 of contact question mark to await 　 　 Serial 1 second.

ReadData(&read_BUFFER, 1);// is read take PLC to answer If(read_BUFFER of question mark 　=={of ACK) 　 　 if PLC answers question mark to be equal to ACK, have 4 kinds of afore-mentioned operations: Serial of}} 　 　 .

After Close():// operation completes, shut 　 of communication mouth} mouth of 3 process designing command operation 　 (1) component or word component condition read operation operand component: Component of the X of PLC interior, Y, M, S, T, C, D; Order form: Explain: ① commands initiative mark STX to read, code is OX02; ② is a component or word component condition reads command CMDO, command code is OX30; ③ is 4 when read a component or word component initiative addresses, perch is sent first, low late, and it is the form that piles up with ASCII is sent; ④ takes a number of a component or word component to be read, most readable take OXff the component of byte, the form that piles up with ASCII is sent; ⑤ is stop a mark ETX, code is OX03; ⑥ is mixed for 2 desired result, it is ② , ③ , ④ with accumulative total code, take its and minimum two are changed into ASCII code, perch is sent first, low late. Nextpage 　 is in after sending afore-mentioned order form code, can read the news that takes PLC to answer directly. Answer news format to be as follows: Language of VC ＋ ＋ comes true: BOOL CNTJDlg: ReadFromPLC(char *Read_char Char*Read_address, serial of 　 of Int I; 　 of 　 of 　 of Int Datasum_check=0; of 　 of 　 of Char Readdatasum_check[2];int Readdata_sum; of 　 of 　 of Char Senddatasum_CHECK[2];char Readdatasum_CHECK[2]; Char Total_DATABYTES[2]; of 　 of Int Read_bytes){　 .

SendData(&STX_start, 1);/ is sent to PLC " begin " Serial of mark code 　 .

SendData(&CMDO_read, 1);// is sent " read " For(i=0;i<4;i++){Serial of 　 of 　 of command code Datasum_check+=CMDO_read; .

SendData(&Read_address[i] , the Change To Asci(total DATABYTES of 　 of 　 of ASCII code Datasum_check+=Read_address[i];} that 1);// delivers initiative component address, read_bytes);// changes byte number into For (i=0;i<2;i++){Serial of ASCII code 　 .

SendData(&total_DATABYTES[i] , the ASCII code that 1);// sends component byte to count) Serial of Datasum_check+total_DATABYTES[i];} 　 　 .

SendData(&ETX_end, 1);// is sent " end " Change_to_asci(senddatasum_CHECK of 　 of 　 of mark code Senddatasum_CHECK+ETX_end; , senddatasum_CHECK);// will " and " change into ASCII to pile up 　 For (i=0;i<2;i++) Serial.

SendData(&senddatasum_CHECK[i] , sleep(1000);// of 1); 　 　 awaits PLC to answer 　 Serial.

ReadData(&read_BUFFER, if(read_BUFFER of 1); 　 　==For(i=0;i<2*Read_bytes;i++){Serial of 　 of 　 of 　 of 　 of Readdata_sum=0; of 　 of 　 of STX_start){　 　 .

ReadData(&Read_char[i] , 1);// reads Read_bytes Serial of 　 of 　 of 　 of byte Readdata_sum+Read_char[i];} 　 .

ReadData(&read_BUFFER, if(read_BUFFER of 　 of 　 of 1); 　 　==ETX_end){Serial.

ReadData(readdatasum_CHECK, 2);// reads in " and " low Change_to_asci(readdatasum_check of 　 of 　 of 　 of Readdata_sum+=ETX_end;} of 2 ASCII code, readdata_sum);// receives consideration " and " change into ASCII to pile up 　 　 If(*readdatasum_CHECK==*Readdatasum_check)// " and " AfxMessageBox(of 　 of {of desired result 　 " data numerates successful! " ) 　 AfxMessageBox(of Else {of 　 of 　 of Return TRUE;} 　 " desired result mistake " ) Return FALSE.

}} 　 　 (2) component or word component condition keep operation operand component: With 3(1) ; Order form: Explain: ① commands initiative mark STX to write, code is OX02; ② is a component or word component condition writes command CMD1, command code is OX31; ③ is 4 when keep a component or word component initiative addresses, perch is sent first, low late, and it is the form that piles up with ASCII is sent; ④ keeps a number of a component or word component for, the form that piles up with ASCII is sent; ⑤ writes the data DATA of PLC RAM area to wait for, with ASCII code form is sent; ⑥ is stop a mark ETX, code is 2 for ⑦ of 　 of OX03; 　 　 with desired result, it is ② , ③ , ④ with accumulative total code, take its and minimum two are changed into ASCII code, perch is sent first, low late. Language of VC ＋ ＋ comes true: BOOL CNTJDlg: WritePLC(char *data_ADDRESS, char *Write_ASC, serial of 　 of 　 of 　 of Int Datasum_check=0; Int I=0; of 　 of 　 of 　 of Char Read_BUFFER;char Read_finishBUFFER; of 　 of 　 of 　 of Char Total_BYTES[2];char Senddatasum_CHECK[2]; of 　 of 　 of 　 of {of 　 of Int Bytesnumber) 　 .

SendData(&STX_start, 1);// is sent to PLC " begin " Datasum_check=0;Serial of 　 of mark code 　 .

SendData(&CMD1_write, 1);// is sent " write " For(i=0;i<4;i++) {Serial of 　 of 　 of 　 of Datasum_check+CMD1_write; of 　 of command code 　 .

SendData(&data_ADDRESS[i] , the ASCII that 1);// delivers initiative component address piles up Change_to_asci(total_DATABYTES of 　 of 　 of 　 of 　 of 　 　 Datasum_check+=data_ADDRESS[i]; , bytesnumber);// changes byte number into ASCII to pile up Serial of 　 of 　 of 　 of {of 　 of 　 For(i=0;i<2;i++) 　 .

SendData(&total_BYTES, the 　 of 　 of 　 of Datasum_check+=total_BYTES[i];} of 　 of ASCII code 　 that 1);// sends component byte to count Serial of 　 of 　 of 　 of Int Sum=0; of 　 of 　 of 　 of Char Read_buffer; of 　 of 　 of 　 of Syn_Check[2]; of │ of Char of 　 of 　 of 　 of I; of 　 of {Int of 　 of 　 of For {i=0;inOperation (char *ON_Address) .

SendData(&STX_start, 1);// is sent to PLC " begin " Serial of 　 of mark code 　 .

SendData(&CMD7_ForceON, 1);// is sent " ON " For (i=0; I<4; I++) {Serial of 　 of 　 of 　 of Sum+=CMD7 ForceON; of 　 of command code 　 .

SendData(&ON_Address[i] , the ASCII that 1)// delivers initiative component address piles up Serial of 　 of 　 of 　 of ｝ of 　 　 Sum+=ON_Address[i]; .

SendData(&ETX_end, 1);// is sent " end " Change_to_asci(Sum_Check of 　 of 　 of 　 of mark code Sum+=ETX_end; , sum);// will " and " change into ASCII to pile up 　 　 Serial.

SendData(&Sum_Check, serial of 　 of 　 of 　 of Sleep(1000); of 　 of 2); 　 　 .

ReadData(&read_buffer, if(read_finishBUFFER of 　 of 1); 　 　==ACK_reply) AfxMessageBox(" ON operates OK " ) ; Else AfxMessageBox(" ON handles failure " ) . } 　 　 (4) L of operand of compulsive OFF operation is the same as component 3(3) ; Order form: Explain: ① commands initiative mark STX for compulsive OFF, code is OX02; ② commands CMD8 for compulsive OFF, command code is OX38H; ③ is compulsive OFF component 4 initiative addresses, perch is sent first, low late, with ASCII code form is sent; ④ is stop a mark ETX, code is OX03; ⑤ is mixed for 2 desired result, it is ② , ③ , ④ with accumulative total code, take its and minimum two are changed into ASCII code, perch is sent first, low late. Language of VC ＋ ＋ comes true: Void NTJDlg: Serial of 　 of 　 of Int Sum=0; of 　 of 　 of Char Read_buffer; of 　 of 　 of Char Sum_Check[2]; of 　 of Int I; 　 of 　 of 　 of {of 　 of 　 of ForceOffOperation (char *OFF_Address) .

SendData(&STX_start, 1);// is sent to PLC " begin " Serial of mark code 　 .

SendData(&CMD8_ForceOFF, 1);// is sent " OFF " Serial of 　 of 　 of 　 of For (i=0;i<4;i++) {of 　 of 　 of Sum=CMD8_ForceOFF; of command code 　 .

SendData(&OFF_Address[i] , the ASCII that 1);// delivers initiative component address piles up Serial of 　 of 　 of 　 　 Sum+=OFF_Address[i];} .

SendData(&ETX_end, 1);// is sent " end " Change_to_asci(Sum_Check of 　 of 　 of Sum+=ETX_end; of mark code 　 , sum);// will " and " change into ASCII to pile up 　 Serial.

SendData(&Sum_Check, serial of 　 of 　 of Skeeo(1000); of 2); 　 　 .

ReadData(&read_buffer, if(read_fininhBUFFER of 1); 　 　==ACK_reply) AfxMessageBox(" OFF operates OK " ) ; Else AfxMessageBox(" OFF handles failure " ) . ｝ 　 notices: Must command according to 4 kinds of afore-mentioned operations the format undertakes sending strictly, before send, initiative address, data, data number, desired result and must positional changeover is piled up into ASCII. The data that reads from PLC also is ASCII code form, need to be used through changing ability appropriately. Additional, like wanting to notice to command address and the order that read address are not compulsively, and can convey only at most 64 byte data. 4 conclusion use orders of afore-mentioned 4 kinds of operations, can be opposite the RAM area data of PLC undertakes administrative operating. Under management of the in a subtle way of working state offer PLC computer. On this foundation, the user can apply VC very the interface of PLC man-machine interface that designs oneself conveniently, move with what manage PLC for monitoring provide a kind of good means. CNC Milling CNC Machining