The following public member functions are provided as part of the tpriABPlc class:

• tpriABPlc *pABPlc = new tpriABPlc;

  • Allocate a new tpriABplc object

• destroy (tpriABPlcPlc *)pABPlc();

  • Destroy the tpriABPlc class object.
    

• int Config (char *pHostName, int timeout);

where:

char *pHostName= host name or IP address

int timeout = time value for read and write operation in milliseconds

This function stores new configuration information for use by class functions

•  int GetConnStatus (void);

where:

return status = connection status

                        0 = unconnected

1 = connected

This function returns the status of the connection between the Compute system and the PLC

• int SetReadFile(char *file, int offset, int num);
  where:
  char *file = PLC file name from which to read data
  int offset  = byte offset from start of ‘filename’ from which to read data
  int num = number of data items to read

This function stores the PLC read control information for use by the ScanIO class member

• int SetWriteFile(char *file, int offset, int num);
  where:
  char *file = PLC file name where to write data
  int offset  = byte offset from start of ‘filename’ to write data
  int num = number of data items to write

This function stores the PLC read control information for use by the ScanIO class member

•  int Connect (void);

This function establishes a connection between the computer system and the PLC

•  int Disconnect (void);

This function breaks a connection between the computer system and the PLC

•  int ScanIO (int *igram, int *ogram, int *ipsta);

where:
int *igram = user memory address where PLC read data will be returned

int *ogram = user memory address where PLC write will be obtained

int *ipsta = addr of an integer variable where I/O status will be returned

This function first reads a single data block of 16 bit integers values from the PLC user register memory and then writes a block of 16 bit integers to the PLC memory.  The plc locations for the read and write are obtained from prior calls to the SetReadFile90 and SetWriteFile() functions.

int tpriRdcLts::open(int *devHndl, char *devName, int portNum, int blocking = -1, struct sockaddr_in *pServer = NULL)

This function is identical to that for the tpriRdcTcp class with the following exception:

Inputs:

int portNum      Desired port number on the terminal server, starting with 1.

int tpriRdcLts::close(int devHndl)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcLts::read(int devHndl, char *rxBuf, int rxCnt, int blocking = -1)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcLts::write(int devHndl, char *txBuf, int txCnt)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcLts:: resetConn(char *devName, int ltsPort, char *password = NULL)

Reset a port on a Lantronix terminal server.  This is useful if a connection to the terminal server died unexpectedly such that the server thinks the connection is still present and will not allow new connections until the original is reset.

Inputs:

char *devName      Remote device name.

int ltsPort      Desired port number on the terminal server, starting with 1.

char *password      The privileged password on the terminal server.  If no password is provided "system" is assumed.

Return value:

If a connection was made to the terminal server then a zero will be returned regardless of whether or not the reset was successful.  A return value of -1 indicates that a connection could not be established.

Following is an example class definition and source code for a Lantronix driver using the static function calls above to loop a message through a port on a terminal server back into itself.  It requires that a loopback cable be plugged into the specified port on the Lantronix terminal server.

<DemoLts.cpp>
//------------------------------------------------------------------------
//    File Name        : DemoLts.cpp
//
//    Author           : TelePro, Inc.
//
//    Date (Original)  : 6/15/01
//
//    Hdwr/Sys Config  : Pentium III PC or greater
//                       Windows 2000
//
//    Revision History :
//    Rev     Date       Who/Description
//    1.00    06/15/01   AJ Johnson
//                       Initial Version 
//------------------------------------------------------------------------
//    COPYRIGHT (C) 2001
//    TELEPRO, INC.
//    ALL RIGHTS RESERVED
//
//    THIS SOFTWARE AND ALL INFORMATION AND IDEAS CONTAINED WITHIN
//    ARE THE PROPERTY OF TELEPRO, INC. AND ARE CONFIDENTIAL.
//    NEITHER THIS SOFTWARE NOR ANY PART NOR ANY INFORMATION
//    CONTAINED IN IT MAY BE DISCLOSED OR FURNISHED TO OTHERS
//    WITHOUT THE PRIOR WRITTEN CONSENT OF TELEPRO, INC.
//------------------------------------------------------------------------
//    Function Name: DemoLts
//
//    Function Description and Notes:
//         This program demonstrates communications through a Lantronix
//         terminal server using a loopback test and the static class
//         tpriRdcLts functions to connect, read, write, and close.
//
//    Function type:
//       "C" language void function
//------------------------------------------------------------------------

// Standard header includes
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>

// System specific header includes
#include "tpriNtRt.h"
#include "tpriRdcLts.h"

void _cdecl main(int argc, char **argv, char **envp)
   {
   // Variable declarations
   int rstatus = 0;        // this function's return status
   int fstatus = 0;        // function call return status
   int forever = 1;        // Set => 0 when processing loop should exit
   char rxBuf[128];
   char rxCnt = 0;
   char *txBuf = "Test loopback message";
   int txCnt = strlen(txBuf);
   int devHndl = -1;
   char devName[256];
   int portNum;
   int connStat;
   // --------------------------------------------------------------
   // Initialize process management global
   // ------------
   fstatus = tpriProc::Create();
   if (fstatus < 0)
      {
      // unable to initialize process
      LogMsg("DemoLts", DBSS, "Error initializing process commons\n");
      forever = 0;
      }
   else
      {
      LogMsg("DemoLts", DBSS, "DemoLts V1.00\n");
      }
   // --------------------------------------------------------------
   // Set up local process environment using process initialization
   // file parameters
   // --------------------------------------------------------------
   if (forever)
      {
      fstatus = tpriProc::PrIni(argc, argv);
      if (fstatus < 0)
         {
         // unable to initialize process
         LogMsg("DemoLts", DBSS, "Error initializing process\n");
         forever = 0;
         }
      }
   // --------------------------------------------------------------
   // Application Code:
   //     The following code will be run once on initial process execution
   // --------------------------------------------------------------
#ifndef UNDER_RTSS
   WSADATA wsaData;
   int socketInit;
   if (forever)
      {
      // set up windows sockets
      socketInit = WSAStartup(0x0020, &wsaData);
      if (socketInit != 0)
         {
         // error initializing windows sockets
         LogMsg("DemoLts", DBERR, "Error %d starting Windows sockets\n",
            GetLastError());
         forever = 0;
         }
      }
#endif

   if (forever)
      {
      if (argc <= 1)
         {
         LogMsg("DemoLts", DBFERR, 
            "Ini file not specified on command line\n");
         forever = 0;
         }
      else
         {
         // get the LTS IP address
         tpriIniFile::getKeyValue("LtsLoopback", "IPAddress", "localhost", 
            devName, sizeof(devName), argv[1]);

         // get the LTS port number
         tpriIniFile::getKeyValue("LtsLoopback", "LtsPort", "1", 
            rxBuf, sizeof(rxBuf), argv[1]);
         portNum = atol(rxBuf);
         }
      }

   // --------------------------------------------------------------
   // Try to connect
   // -------------------------------------------------------------
   while ((forever) && 
          ((connStat = tpriRdcLts::open(&devHndl, devName, 
                                        portNum, 0)) < 0))
      {
      // -----------------------------------------------------------
      // Call PrWait to stall until the next timer interval
      // -----------------------------------------------------------
      fstatus = tpriProc::PrWait();

      // --------------------------------------------------------
      // Decide whether or not to continue
      // -------------------------------------------------------
      forever &= (tpriProc::getState() > 0);
      }

   if (connStat == 0)
      {
      LogMsg("DemoLts", DBSS, "Connected to terminal server %s port %d\n",
         devName, portNum);

      // write a message out to the terminal server
      if (tpriRdcLts::write(devHndl, txBuf, txCnt) != txCnt)
         {
         LogMsg("DemoLts", DBERR, 
            "Error writing data to terminal server\n");
         }
      else 
         {
         LogMsg("DemoLts", DBERR, 
            "Wrote loopback message <%s> to terminal server\n", txBuf);

         while (forever)
            {
            // read a bit of data
            fstatus = tpriRdcLts::read(devHndl, &rxBuf[rxCnt], 
                         sizeof(rxBuf) - rxCnt, 0);
            if (fstatus > 0)
               {
               // print out what we just received
               DumpHex(DEBUG, (unsigned char *)&rxBuf[rxCnt], 0, fstatus,
                  "Received data");

               // check if this new data completes the message
               rxCnt += fstatus;

               if (memcmp(rxBuf, txBuf, txCnt) == 0)
                  {
                  // bingo! - we got back what we sent
                  rxBuf[txCnt] = 0x00;
                  LogMsg("DemoLts", DBSS, 
                     "Received full loopback message <%s>\n", rxBuf);

                  // fall out of the loops
                  forever = 0;
                  }
               }
               
            // -----------------------------------------------------
            // Call PrWait to stall until the next timer interval
            // -----------------------------------------------------
            fstatus = tpriProc::PrWait();
            
            // ---------------------------------------------------
            // Decide whether or not to continue
            // ---------------------------------------------------
            forever &= (tpriProc::getState() > 0);
            }
         }
         
      // close the connection
      tpriRdcLts::close(devHndl);
      }
   // ----------------------------------------------------------
   // At this point the Application has decided that it no longer wants
   // to be run, so clean up and exit.
   // ------------------------------------------------------------
   LogMsg("DemoLts", DBSS, "Process exiting\n");
   tpriGsmDDCom::Destroy();
   tpriProc::Destroy();

   ExitProcess(rstatus);
   }

<LtsLoopback.ini>

#
#   Example Lantronix terminal server loopback program config file
#
[LtsLoopback]
IPAddress=192.55.195.222
LtsPort=1

The I/O driver library includes the tpriRdcCbx class for communications through a Lantronix CoBox terminal server to a remote device.  This class provides functions to open a connection to a specified port on the desired CoBox terminal server, to read and write data to and from the device attached to the terminal server, and to close the connection when finished.  Blocking and non-blocking modes are both supported individually for connections and reads.  The library is composed of several static class functions that can be explicitly called without having to manage the underlying class itself.

int tpriRdcCbx::open(int *devHndl, char *devName, int portNum, int blocking = -1, struct sockaddr_in *pServer = NULL)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcCbx::close(int devHndl)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcCbx::read(int devHndl, char *rxBuf, int rxCnt, int blocking = -1)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcCbx::write(int devHndl, char *txBuf, int txCnt)

This function is identical to that for the tpriRdcTcp class.

int tpriRdcCbx:: resetConn(char *devName, char *password = NULL)

Reset a port on a CoBox terminal server.  This is useful if a connection to the terminal server died unexpectedly such that the server thinks the connection is still present and will not allow new connections until the original is reset.

Inputs:

char *devName      Remote device name.

char *password      The privileged password on the terminal server.  If no password is provided "system" is assumed.

Return value:

If a connection was made to the terminal server then a zero will be returned regardless of whether or not the reset was successful.  A return value of -1 indicates that a connection could not be established.

In addition to the static library functions described above, the tpriRdc-derived classes can be used to as a framework to manage all of the low-level I/O, timing, and error recovery associated with a connection to a remote device.  In effect, the tpriRdc classes act as a fully customizable state machine to communicate with a remote device through a variety of interfaces without having to worry about the specifics of the intermediate hardware or basic communications protocols.  Currently, the following interfaces are supported:

• Direct serial RS-232

• Direct TCP/IP

• TCP/IP to serial via Lantronix 4-, 8-, and 16-port terminal servers

• TCP/IP to serial via Lantronix CoBox single-port terminal servers

The interface-specific tpriRdc classes are:

• tpriRdcSer           Direct serial RS-232

• tpriRdcTcp           Direct TCP/IP

• tpriRdcLts            Lantronix multi-port terminal server

• tpriRdcCbx           Lantronix CoBox terminal server

The custom device driver should be derived from one of these classes in order to build upon and use the functionality encapsulated within these classes.

Following is flow path for the state machine:

switch (current state)

      case UNINIT

• call virtual function initDrv()

case IDLE

• if first pass → goto state CONNECT

• else if reopen

  • set/test delay timer for reopen

• else return non-zero from state driver to indicate we’re finished

case CONNECT

• call virtual function setupComm(0) to open connection

• if success → goto state WAITMSG

• else if error →

  • call virtual function setupComm(1) to clean up

case WAITMSG

• call virtual function waitMsg() to check if it’s time to send a message

• if it’s time → goto state BUILDMSG

• else if it’s not yet time → continue waiting

case BUILDMSG

• call virtual function buildMsg() to assemble the outbound message

• if return = 0 → goto state XMITMSG

• else if error → return to state WAITMSG

case XMITMSG

• call virtual function xmitMsg() to send message

• if return = 0 → goto state WAITRSP

• else if error →

  • call virtual function setupComm(1) to clean up

  • return to state IDLE

case WAITRSP

• call waitRsp() to read data from interface

• call virtual function testRsp() to test if a full msg has been recv’d.

• if full msg recv’d → goto state PROCRSP to process valid message

• else if timeout → goto state PROCRSP to process empty message

• else if error →

  • call virtual function setupComm(1) to clean up

  • return to state IDLE

case PROCRSP

• call virtual function procRsp()

• if return is 0 → goto state WAITMSG

• else if error → goto state IDLE

The state machine for the remote device connection can be executed by calling the following function defined in the tpriRdc base class:

int tpriRdc:: stateDrv(int oneshot = 0)

Close a connection associated with a device handle.

Inputs:

int oneshot      If non-zero, the state machine will execute only once and return.  If zero, the state machine will repeatedly execute until the current state does not change from pass to pass. 

Return value:

Zero if no error and state machine can be called again to continue processing or non-zero if an error has occurred or the state machine has finished.

The state machine for the remote device connection can be executed by calling the following function defined in the tpriRdc base class:

The following variables are internal data members of the tpriRdc class and the custom driver class should set their values as desired:

The following variables are internal data members of the tpriRdcTcp class the custom driver class should set their values as desired:

The following variables are internal data members of the tpriRdc class that the custom device class will require for normal processing:

The custom device driver class then overrides a set of virtual functions that will be called by the base classes at the appropriate times.  These virtual functions are:

• Virtual int initDrv()
  The framework calls this function to process one-time initialization of internal parameters including device name, timeout values, max retry counts, etc.  Return zero to indicate success and nonzero to indicate that an error has occurred.
  

•  Virtual int setupComm(int oper)
  The framework calls this function to connect (oper <> 0) or disconnect (oper = 0) from the remote device.  Return zero to indicate success and nonzero to indicate that an error has occurred.  This function does not need to be overridden under normal circumstances.
  

•  Virtual int waitMsg()
  The framework calls this function to allow the derived class to decide when it is time to send a message to the remote device.  Return zero to indicate a message should now be sent and nonzero to continue waiting.
  

•  Virtual int buildMsg()
  The framework calls this function to assemble the next outbound message immediately after the user has returned zero from a call to waitMsg().  The custom driver should copy the outbound message into the class data member txBuf[] character buffer and store the number of characters in the class data member txCnt.
  

•  Virtual int xmitMsg()|
  The framework calls this function to transmit data to the remote device.  Return 0 to indicate success or nonzero indicate an error.  This function does not need to be overridden under normal circumstances.
  

•  Virtual int waitRsp()
  The framework calls this function to read data from the remote device.  It must also call testRsp() to check if a full message has been received.  Return 0 to indicate reception of a complete message or timeout or -1 to continue reading data.  This function does not need to be overridden under normal circumstances.
  

•  Virtual int testRsp()
  The framework calls this function to decide whether or not a response has been received from the remote device.  Upon entry into this function all data received from the remote device since transmission of the most recent message is stored in the class data member rxBuf[] character buffer and the number of received bytes stored in rxCnt.  Any bytes at the beginning of the rxBuf[] buffer that are not part of a valid response may be removed using the class member function tossRsp(int nToss).  If a valid message is found, copy it from the beginning of the rxBuf[] buffer to the response buffer using the class member function ripRsp(nRsp).  Return zero to indicate that the response is complete, less than zero to indicate that the response is incomplete, and greater than zero to indicate that an error has occurred.
  

•  Virtual int procRsp()
  The framework calls this function to process a complete response from the remote device.  Return zero to reset and wait until the next message should be sent, and nonzero to reset the connection.

The following functions are internal data methods of the tpriRdc class for use within the custom user driver:

int getState()

Return the current state.

Return value:

The current state is returned as specified in the following table:

UNINIT            0

IDLE            1

CONNECT           2

WAITMSG           3

BUILDMSG          4

XMITMSG           5

WAITRSP           6

PROCRSP           7

void setRxBufSize(int size)

Resize of the internal receive buffer.  Any data existing in the existing buffer will be transferred to the new buffer provided that it does not exceed the new size.  The default size of the receive buffer is 1024 bytes.

Inputs:

int size      New size of receive buffer.

void setTxBufSize(int size)

Resize of the internal transmit buffer.  Any data existing in the existing buffer will be transferred to the new buffer provided that it does not exceed the new size.  The default size of the transmit buffer is 1024 bytes.

Inputs:

int size      New size of transmit buffer.

void ripRsp(int nRsp)

Pops the first nRsp bytes from the receive buffer rxBuf[], dynamically allocates the response buffer *rspBuf, and stores the response there for later processing.  This function should be called from within the testRsp() virtual function once a full response starting at the beginning of the rxBuf buffer has been detected.  Each call to ripRsp(..) destroys the response buffer created by the previous call and shifts the receive buffer so that the remaining data is stored at the beginning of the buffer.

Inputs:

int nRsp      Number of bytes in the detected response that should be copied out of the receive buffer rxBuf[].

      void tossRsp(int nRsp)

Pops the first nRsp bytes from the receive buffer rxBuf[] and throws them away.  The receive buffer is then shifted so that the remaining data is stored at the beginning of the buffer.  This function should be called from within the testRsp() virtual function to throw away bytes at the beginning of the receive buffer that are not part of a valid response.

Inputs:

int nRsp   Number of bytes in the detected response that should be copied out of the receive buffer rxBuf[].

The Tsentry source distribution area contains an example class definition and source code for a tpriRdc-derived class used to loop a message through a port on a Lantronix multi-port terminal server back into itself.  It requires that a loopback cable be plugged into the specified port on the Lantronix terminal server.

This driver:

• Communicates with A-B Control Logix 5500 and 5555 PLC systems

• Uses TCP/IP Communications over:

  • Standard Ethernet network connection

  • High Speed dedicated process I/O network with deterministic network performance

• Software implemented as a C++ Class

• Multiple PLC support

• Supports:

  • Read Variables

  • Write variables

Capable of running 500ms Input and Output scan rep rates, depending on data buffer size.

The Allen Bradley PLC must be set up with the proper IP address.  This configuration is completed with the A-B software.  The IP must be chosen such that it lies within the subnet selected for the specific Ethernet controller used for communications.

If the Ethernet controller is one that is controlled by the Windows 2000 system, the subnet is specified in the network setup utility of the control panel.

If the Ethernet controller is one that is controlled by the RTX Real-Time TCP/IP controller, the IP address is specified in the file d:\LocNtRt\sys\pif\RtxTcp.ini. 

The core of the driver is provided as a C++ class that implements the initialization and communications functions.  A sample process is provided which calls the appropriate class members.

The IP address, configuration information, and data areas to be read and written are passed as calling parameters to the class functions.

The following is a list of the provided driver files.  After review of the example driver, the user is required to modify the files as indicated:

The Tsentry CLeip class encapsulates the functionality required to communicate with the Allen Bradley 5500 and 5555 PLCs over a TCP/IP network.

The following public member functions are provided as part of the tpriCLeip class:

•  tpriCLeip *pCLeip = new tpriCLeip;

  • Allocate a new tpriCLeip object

• destroy (tpriCLeip *)pCLeip();

  • Destroy the tpriCLeip class object.
    

•  int SetTraceLevel (int TraceLevel);

where:

int TraceLevel = debug trace level for class operations

                           default value = 30

                           valid values range between 0 and 100, inclusive

                           lower values produce less debug information

                           higher values produce more debug information

                           debug information written using LogMsg function

This function stores a new value for the TraceLevel parameter

• int SetEnetPort (int port);

where:

int port = Ethernet Port number

            Default value = 1

This function stores a new value for the Ethernet Port parameter.  This communications parameter defines the port number for the Ethernet controller in the PLC chassis

• int SetLogixSlot (int slot);

where:

int slot = Control Logix process slot number

            Default value = 0

This function stores a new value for the Ethernet Port parameter.  This communications parameter defines the slot in which the Control Logix processor resides.

• int SetTimeOut (int sTimeOut, int rTimeOut, unsigned char ticktime,

                              unsigned char timeoutticks, unsigned char timeoutmultiplier,

                              unsigned long otrpi, unsigned long torpi );

where:

int sTimeOut = TCP Send message timeout value in milliseconds

                                    Default value = 2000

int rTimeOut = TCP Receive message timeout value in milliseconds

                                    Default value = 2000

unsigned char ticktime = (optional) Protocol Tick time (see below)

                              Default value = 10
                              Minimum value = 0
                              Maximum value = 15

unsigned char timeoutticks = (optional) TickTimes multiplier (see below)

Default value = 14

Minimum value = 1

Maximum value = 255

unsigned char timeoutmultiplier = (optional) Inactivity timeout (see below)

Default value = 1

Minimum value = 1

Maximum value = 255

unsigned long otrpi = (optional) Originator->Term Reqested packet interval (u-sec)

Default value = 2064960

unsigned long torpi = (optional) Terminator->Orig Reqested packet interval (u-sec)

                                     Default value = 2064960

This function stores timeout parameter values for use by the member functions of the class.

The values sTimeOut and rTimeOut are used to determine the maximum time that will elapse for a single user level call (read or write, respectively) to transfer data to or from the PLC.  If this timeout is exceeded, the I/O request will return to the caller indicating a timeout has occurred.

The remaining values are used to define the PLC’s connection session timeout information.  The values ticktime and timeoutticks are used to calculate the maximum time allowed for a connection request to be serviced by the PLC.  If the PLC cannot establish a connection session within this amount of time, the Connect method will return to the caller an error indicating that a timeout has occurred.  This timeout value is calculated by the following formula:

Connection_Timeout (ms) = 2^(ticktime) * timeoutticks

The values timeoutmultiplier otrpi (which stands for Originator->Terminator Requested Packet Interval) and torpi (Terminator->Originator Requested Packet Interval) determine the inactivity timeout of the PLC session.  If this timeout is exceeded BETWEEN calls to the driver (more precisely, between protocol messages sent between the control system and the PLC), the PLC connection session will time out, and the connections to the PLC must be rebuilt.  Subsequent user calls to the driver to transfer data between the control system and the PLC will find the connection destroyed and will return an error.  This timeout value is calculated by the following formula:

Inactivity_Timeout (u-sec) = 4 * 2^(timeoutmultiplier) * min (otrpi, torpi)

Using the default values, the connection timeout and inactivity timeout are:

Connection_Timeout (ms) = 2^(ticktime) * timeoutticks

= 2^10 * 14

= 1024 * 14

= 14336

Connection_Timeout (seconds) = 14.336

Inactivity_Timeout (u-sec) = 4 * 2^(timeoutmultiplier) * min (otrpi, torpi)

= 4 * 2^1 * min (2064960, 2064960)

= 4 * 2 * 2064960

= 16519680

Inactivity_Timeout (seconds) = 16.51968

• int SetConnectionID (unsigned int connid);

where:

unsigned int connid = Logical Connection ID

                       Default value = 0x0b000100

This function stores a new value for the Logical Connection ID parameter

• int SetConnectionSN (unsigned short connsn);

where:

unsigned short connsn = Logical Connection Serial Number

This function stores a new value for the Logical Connection Serial Number

• int SetOriginatorInfo(unsigned short vendorid,  unsigned int sn);

where:

unsigned short vendorid = Originator (local system) vendor ID

default value = 1

unsigned int sn = Originator Sequence Number

default value = 0xBC1C0042

This function stores new values for the Originator (local system) information

• int Connect (char *hostname, short int port);

where:

char *hostname = host name, or

IP addresses expressed as a character string

short int port = TCP/IP port number name, or

This function establishes a connection between the computer system and the Allen-Bradley Control Logix PLC. Note that if a connection has already been established with a given connection serial number, no other connection may be made to that PLC with the same connection serial number until that connection is either gracefully disconnected or has timed out due to inactivity.

• int Disconnect ();

This function breaks a connection between the computer system and the Allen-Bradley Control Logix PLC

• int readClPccc (int adrType, void *FileName, int offset, int noElements,

                                 int dataType, void *buf);

where:

int adrType = address type

void *FileName = file name within PLC from which to read data

int offset = offset (in data variables) from which to start data read

int noElements = number of data elements to read

int dataType = type of data to be read

void *buf = address of user supplied data buffer

This function reads a single data block from the PLC and stores the results in a user defined buffer.

Offsets may work in one of two ways.  If the PLC contains a variable array called by a file name of “PLCVars”, function calls to retrieve data starting at the 61st element of this array could contain 2nd and 3rd arguments of:

“PLCVars”, 60

or,

“PLCVars[60]”, 0

Legal values for the dataType argument are:

CL_SINT – 1-byte integers

CL_INT – 2-byte integers

CL_DINT – 4-byte integers

CL_REAL – IEEE 4-byte floating point numbers

• int writClPccc (int adrType, void *FileName, int offset, int noElements,

                                 int dataType, void *buf);

where:

int adrType = address type

void *FileName = file name within PLC to write user data

int offset = offset (in data variables) from which to start data write

int noElements = number of data elements to write

int dataType = type of data to be written

void *buf = address of user supplied data buffer containing write data

This function writes a single data block to the PLC from the user defined buffer. Offsets may work in one of two ways. If the PLC contains a variable array called by a file name of “PLCVars”, function calls to write data starting at the 61st element of this array could contain 2nd and 3rd arguments of:

“PLCVars”, 60

or,

“PLCVars[60]”, 0

Legal values for the dataType argument are:

CL_SINT – 1-byte integers

CL_INT – 2-byte integers

CL_DINT – 4-byte integers

CL_REAL – IEEE 4-byte floating point numbers

• int readClCip (void *FileName, int offset, int noElements, int *dataType, void *buf);

where:

void *FileName = file name within PLC from which to read data

int offset = offset (in data variables) from which to start data read

int noElements = number of data elements to read

int *dataType = pointer to an integer variable where the type of the data read shall be returned

void *buf = address of user supplied data buffer

This function reads a single data block from the PLC and stores the results in a user defined buffer.

Legal values returned in the dataType variable are:

CL_SINT – 1-byte integers

CL_INT – 2-byte integers

CL_DINT – 4-byte integers

CL_REAL – IEEE 4-byte floating point numbers

•  int writClCip (void *FileName, int offset, int noElements, int dataType, void *buf);

where:

void *FileName = file name within PLC to write user data

int offset = offset (in data variables) from which to start data write

int noElements = number of data elements to write

int dataType = type of data to be written

void *buf = address of user supplied data buffer containing write data

This function writes a single data block to the PLC from the user defined buffer.

Legal values for the dataType argument are:

CL_SINT – 1-byte integers

CL_INT – 2-byte integers

CL_DINT – 4-byte integers

CL_REAL – IEEE 4-byte floating point numbers

Some comments on the driver program are below:

This test program, on each expiration of the process timer, writes a single block of data to the PLC and then reads a single block of data.  This sequence, the number of reads and writes, their addresses, and the sizes of the blocks can be modified to fit the requirements of the application.

PlcUsr and the ‘datagram’ structures they reference should be modified as required to reference appropriate variables in application variables for transfer between the PLC and the control system.

 A sample driver is provided in the examples subdirectories of the standard Tsentry distribution

This driver:

• Communicates with Modicon (Schneider Automation) TSX Quantum PLC systems

• Uses TCP/IP Communications over:

  • Standard Ethernet network connection

  • High Speed dedicated process I/O network with deterministic network performance

• Software implemented as a C++ Class

• Multiple PLC support

• Supports:

  • Read Variables

  • Write variables

Capable of running 500ms Input and Output scan rep rates, depending on data buffer size.

The Modicon PLC must be set up with the proper IP address.  This configuration is completed with the Schneider Automation software.  The IP must be chosen such that it lies within the subnet selected for the specific Ethernet controller used for communications.

If the Ethernet controller is one that is controlled by the Windows 2000 system, the subnet is specified in the network setup utility of the control panel.

If the Ethernet controller is one that is controlled by the RTX Real-Time TCP/IP controller, the IP address is specified in the file d:\LocNtRt\sys\pif\RtxTcp.ini. 

Enough memory must be installed in the PLC to support the data buffer size that will be requested by the software reads and writes.

The core of the driver is provided as a C++ class that implements the initialization and communications functions.  A sample process is provided which calls the appropriate class members.

The IP address, configuration information, and data areas to be read and written are passed as calling parameters to the class functions.

The following is a list of the provided driver files.  After review of the example driver, the user is required to modify the files as indicated:

The Tsentry tpriModPlc class encapsulates the functionality required to communicate with the Modicon Quantum PLCs over a TCP/IP network.

The following public member functions are provided as part of the tpriModPlc class:

• tpriModPlc *pModPlc = new tpriModPlc;

Allocate a new tpriModPlc object

• destroy (tpriModPlc *)pModPlc();

Destroy the tpriModPlc class object.

• int SetTraceLevel (int TraceLevel);

where:

int TraceLevel = debug trace level for class operations

                           default value = 30

                           valid values range between 0 and 100, inclusive

                           lower values produce less debug information

                           higher values produce more debug information

                           debug information written using LogMsg function

This function stores a new value for the TraceLevel parameter

• int SetTimeOut (int sTimeOut, int rTimeOut, unsigned char ticktime,

                              unsigned char timeoutticks, unsigned char timeoutmultiplier,

                              unsigned long otrpi, unsigned long torpi );

where:

int sTimeOut = Send message timeout value in milliseconds

                                    Default value = 2000

int rTimeOut = receive message timeout value in milliseconds

                                    Default value = 2000

This function stores timeout parameter values for use by the member functions of the class

• int int SetDestinationInfo(unsigned char destID);

where:

unsigned short vendorid = Destination ID

default value = 1

This function stores new values for the Destination ID

• int SetPduMaxIoDataBytes (int noBytes);

where:

int noBytes = the maximum number of data bytes that will be placed in a single PDU

                           default value = 125

                           a PDU is a protocol Data Unit and is equivalent to a single Ethernet frame   

                           valid values range between 2 and 125, inclusive

                           lower values may produce more frames to transfer the same user data

                           higher values may produce fewer frames to transfer the same user data

This function sets a new value for the maximum number of user data bytes to be included in a single Ethernet frame (PDU) that is transmitted to the PLC.  A value too low will increase the number of Ethernet frames that will be required to send a given number of user data bytes and reduce throughput. A number too high will not be understood or acknowledged by the PLC.  

• int Connect (char *hostname, short int port);

where:

char *hostname = host name, or

IP addresses expressed as a character string

short int port = TCP/IP port number

This function establishes a connection between the computer system and the Modicon PLC

• int Disconnect ();

This function breaks a connection between the computer system and the Modicon PLC

• int read4x (int offset, int noElements, void *buf);

where:

int offset = PLC memory offset in 16 bit words from which to read data

int noElements = number of 16 bit integer data elements to read

void *buf = address of user supplied data buffer

This function reads a single data block of 16 bit integers values from the PLC user register memory starting at ‘offset’ words from 40000 and stores the results in a user defined buffer

• int writ4x (int offset, int noElements, void *buf);

where:

int offset = PLC memory offset in 16 bit words from which to write data

int noElements = number of 16 bit integer data elements to write

void *buf = address of user supplied data buffer

This function writes a single block of user supplied 16 bit data words to the PLC user register memory starting at ‘offset’ words after 40000

Some comments on the driver program follow:

This test program, on each expiration of the process timer, writes a single block of data to the PLC and then reads a single block of data.  This sequence, the number of reads and writes, their addresses, and the sizes of the blocks can be modified to fit the requirements of the application.

PlcUsr and the ‘datagram’ structures they reference should be modified as required to reference appropriate variables in application variables for transfer between the PLC and the control system.

 A sample driver is provided in the examples subdirectories of the standard Tsentry distribution.

This driver provides an interface to an internal VMIC reflective memory card. It manages both reading and writing variables to the card’s onboard memory, which the card automatically synchronizes with all other cards on the optical network. The driver supports the following:

• Operation in both Win32 and RTSS environment

• Support for both VMICPCI-5576 and VMICPCI-5579 cards

• Ini file configuration of read and write variable transfers

There is no specific card configuration required for the VMIC reflective memory driver. Simply put the card into an empty full-length PCI slot, and the software driver manages the rest.

The VMIC driver is configured by a flat ASCII file divided into [Sections].  The following sections are required in this file:

[General]

This section defines general parameters for the VMIC device.  The parameters are specified in the standard Key=Value pair format.

• DeviceIdx=1

Defines the device index of the card you wish to use. By default this value is 1, and unless you have more than one VMIC card, this parameter is not needed.

• DeviceType=PCI-5576

Defines the card type that you wish to use. Supported values are ‘PCI-5576’ and ‘PCI-5579’ (no quotes).  If this parameter is not specified, the driver will search for the first supported device that it can find.

• ChkOverlap=0

This optional flag sets whether or not the driver will check your variable list to make sure that no two variables overlap one another in the VMIC memory buffer. For instance, two variables may mistakenly both be configured to write to the same bytes on the card. If this flag is set the driver will detect this overlap and fail to initialize. A message will be logged to the console to indicate the offending variables, and the ini file will need to be corrected before the driver will work.  By default this option is enabled; set the flag to 0 to turn it off. 

• IODescFile=d:\MyIODesc.txt

This optional parameter specifies an output text file to which the VMIC driver will write a complete description of all variables and their associated offsets into the VMIC reflective memory buffer.  This is particularly useful when transferring entire structures and you want to know the offsets for each of the constituent variables contained in those structures.

 [VarDef]

This section defines all variables that are to be read from or written to the reflective memory segment. Each line in this section defines a single variable in a set of whitespace-delimited fields:

Empty lines or lines beginning with the ‘#’ symbol are ignored.

The fields for each variable are:

• #VariableName

The variable name within the TSENTRY data dictionary (identical to that used by Probe, etc.).  Besides individual variables, entire arrays or structures may also be specified.

• #Read/Write

Flag specifying whether the variable is to be read from the card (R) or written to the card (W).

• #Offset

Offset into the VMIC onboard memory where this variable is to be read from or written to. This value can be specified in hex with the ‘0x’ prefix or in decimal.  The data will be reflected in the memory of all other VMIC cards in the ring at this same offset. Note that offsets 0x00-0x3F are reserved for use by the VMIC card and cannot be used for reflected data.

• #RemoteType

Optional parameter used if the data on the card should be interpreted in a format different from that inside the PC’s internal memory. Typically this is used if the internal variable is a 4-byte integer but should be read/written as a 2-byte integer. This parameter applies only if an individual variable is specified; it will not automatically convert arrays or elements inside of structures.  The following remote types are supported:

VT_I1        1-byte integer (C/C++ character)

VT_I2        2-byte integer (C/C++ short)

VT_I4        4-byte integer (C/C++ long)

VT_I8        8-byte integer (C/C++ __int64)

VT_R4        1-byte integer (C/C++ float)

VT_R8        1-byte integer (C/C++ double)

The following public member functions are provided as part of the tpriVmic class:

•  tpriVmic::tpriVmic()

  • Constructor for the VMIC driver object.
    

•  tpriVmic::~tpriVmic()

  • Destructor for the VMIC driver object.
    

• int tpriVmic:: initDrv(char *fileName)
  Initialize the VMIC driver with the specified ini file.

  • Inputs:
    char * fileName                        Configuration file name.

  • Return value:
    Zero indicates success, non-zero indicates failure.
    

• int tpriVmic::writeIODesc()
  Write the I/O decription table to the specified file on disk.

  • Inputs:
    char * fileName                        Output file name.

  • Return value:
    Zero indicates success, non-zero indicates failure.

•  int tpriVmic::runDrv()
  Run the VMIC driver state machine.  This function should be called iteratively in the main loop of the driver process.

  • Return value:
    Zero indicates success, non-zero indicates failure.

A sample driver is provided in the examples subdirectories of the standard TSENTRY distribution.