西门子 Modbus TCP 教程.doc

As I think a lot of people involved into the automation world know , Siemens always shown a kind of adversity to equip its products with not-native Siemens protocols. One of these, born on far 1979 but still common, is the Modbus protocol for networks TCP/IP. Anyway, available from few years, Siemens release its on licensed-library in order to use Modbus TCP communication into the PN type CPU (300, 400, 400H), into the CP (343, 443) or into the CPU-PN equipped ET200S. Recently I had the possibility to test this library developing an application (S7-317 2PN/DP) who needs to run as Modbus Master (Client) reading / writings data to some relay controller (Areva) in order to control an hydroelectric power plant. Then I though to wrote this tutorial as a memo for some future similar jobs. Wish itll be usefull you too.Into this article Ill explain hot to implement to modbus TCP Client (Master) functionality into a CPU S7-315 2PN/DP firmware 3.2. Here follow hardware and software needed coponents: Software S7 Open Modbus TCP CPU PN Single License cod.2XV9450-1MB02 v.1.3 (for details take a look at) Software di progettazione Simatic Step 7 v.5.5 service pack 3 CPU S7 315 2PN/DP cod 6ES7315-2EH14-0AB0 + MMC (512kb is enough) Install the Open Modbus TCP CPU PN Single License package. A new Windows menu item will be added into Simatic menu: SIMATIC MODBUS TCP WIZARD. More over the MODBUS_PN_CPU library library will get into your Simatic Step7 resources. Create then a new Simatic project (in this article I call it MbTCP), then add into hardware configuration the CPU and then you can add following FB and the DB (besides the normal needed OB, void unattended CPU stop such as OB80, OB82, OB86, OB121, OB122,.) o FB102 (MODBUSPN) (v.3.4) : this is the heart of Simatic Modbus library . Copy it from the MODBUS_PN_CPU library included in Simatico FB63 (TSEND): copy it from the Standard Library, Communication Blocks included in Simatico FB64 (TRCV):copy it from the Standard Library, Communication Blocks included in Simatico FB65 (TCON): ccopy it from the Standard Library, Communication Blocks included in Simatico FB103 (TCP_COMM): Copy it from the MODBUS_PN_CPU library included in Simatico FB104 (MOD_CLI): Copy it from the MODBUS_PN_CPU library included in Simatico FB105 (MOD_SERV) : Copy it from the MODBUS_PN_CPU library included in Simatico FC10 (EQ_STRING):Copy it from the Standard Library, IEC Function Blocks included in Simatico DB2 (MODBUS_PARAM) : Copy it from the MODBUS_PN_CPU library included in Simatico DB3 (License DB) : Copy it from the MODBUS_PN_CPU library included in Simatic After insert the bottom listed FB and DB, its necessary to specify the Modbus communication parameters such as IP address, TCP port, target registers for R/W,. You can choose 2 way to do it: o Manually: editing the DB2 (MODBUS_PARAM) contained valueo By the Simatic Wizard (I suggest this.easier) Start the Wizard added during the installation of S7 Open Modbus TCP CPU PN Then press Next Into the new open pop-up, set the project you want edit (MbTCP) and the Block directory path (as I show in following picture). Then press Next Into the new open pop-up the Wizard requests to locate the DB2 (MODBUS_PARAM), then click the change option. Then press Next Is time now to define the working mode fo the CPU: Client=Master or Server=Salve. In my sample I set it as Client by click the single write (function code 05/06) option. Then press Next NOTE: Into the pop up Modbus General Parameters, the 3 options means: o 1 Click it if need PLC run as server (Slave), Leave it blank if need to run as Client (Master)o 2 Click it to enable the Modbus writing functionality (reading functionality is always active in Client Mode)o 3 Click it to enable the CPU (in Server mode) auto connect to the Client (do not use it.the FB102 already provides this functionality by its parameters) Into the new open pop-up fill the underlined fields as shown. Then press Next Communication Partners pop up description: o 1 Connection ID (it represent the Simatic internal reference ID).This ID must be provide as Input parameters into the FB102 at the IDo 2 Connection Name (freely editable)o 3 Connection Type (Active=Client=Master, Passive=Server=Slave)o 4 IP Address of communication partner (or TCP/RTU converter if present). It has to be into the same networko 5- Siemens hardware type (CPU, ET200,) Set the communication TCP port (usually the 502). Then press Next Set the read and write targets as show below: NOTE: o 1 - Modbus data type: possible selection between: Coils, Input, Holding Register, Input Registero 2 - first resister to read /write. In case of value 0, it represent the offest. (in my sample I start from 17)o 3 - last register to read /writeo 4 - Target data DB. Into it, the first record correspond to the start Address, 17 in my sample Then press Next If another CPU/project need to be edit then click Configure another connection otherwise click Finish Insert into the S7 project the FB102 instance (onto OB1 or a OB1 called FC/FB) as following shown: The instance DB (namedModbusPN_DI) will create during the call instruction of FB102. Itll contain FB102s requested parameters as:o ID: word=connection ID . It has to be the value specified during wizard (pop up Communication Partners)o DB_PARAM:BLOCK_DB parameters DB (DB2 according to wizard)o RECV_TIME: TIME=max receiving time (time-out)o CONN_TIME: TIME=max establish connection time (time-out)o KEEP_ALIVE:TIME=not usedo ENQ_REQ: BOOL= read/write request (rising edge). Good habit is to manage this bit according to communication status (STATUS_MODBUS) and the DONE_NDR bit (prevoius job done)Parameter In/Out Type Description Value range IDINWORDConnection-ID, must be identical to the associated parameter in the local connection description 1 to 4095 yesDB_PARAMINBLOCK_DBNumber of the parameter DBRECV_TIMEINTIMEMonitoring Time: Wait for data from communication partnerShortest adjustable time is 20 msCONN_TIMEINTIMEMonitoring Time: Wait for establishing or termination of the connectionShortest adjustable time is 100 msKEEP_ALIVEINTIMENot usedENQ_REQINBOOLCP is Client: Initiate request at positive edgeCP is Server: Ready to receive at TRUE signalDISCONNECTINBOOLS7 is Client: TRUE: the connection will be terminated after reception of the responseS7 is Server: TRUE: the connection will be terminated when ENQ_ENR = FALSEREG_KEYINSTRING17Registration key to activate the licenseLICENSEDINBOOLLicense state of the function blockBlock is licensedBlock is not licensedTRUEFALSEBUSYOUTBOOLOperating state of the T-functions (TCON, TDISCON, TSEND or TRCV)Job processingNo job processing activeTRUEFALSECONN_ESTABILISHEDOUTBOOLConnection establishedConnection endTRUEFALSEDONE_NDR OUTBOOLCP is Client: TRUE: Active request finished without errorsCP is Server: TRUE: Request from the client was executed and answeredERROR OUTBOOLAn error has occurred (TRUE)No error has occurred (FALSE)TRUEFALSESTATUS_MODBUS OUTWORDError number for protocol errors when evaluating a Modbus telegram (if 0)STATUS_CONNOUTSTRING8Error number for connection errors during execution of the T-blocks (TCON, TSEND,TRCV, DISON),. (if 0)UNITIN/OUTBYTEUnit i