RMCLink.Connect Method

Establishes a connection with a controller using the settings specified when the RMCLink object was created (device type, port name, host name).

Syntax

Visual Basic (Declaration)

Sub Connect ()

Visual Basic (Usage)

Dim instance As RMCLink

instance.Connect

Remarks

This method is synchronous, which means that it will not return until the connection has been established, or the connection attempt fails and a COM exception is thrown, which may take several seconds to take place. If this method is called on the main thread, then the application will likely be unresponsive until this method completes. For applications where this is not acceptable, this and other synchronous methods should be called from a worker thread, and may use the CancelRequest method to cancel an in progress request.

WARNING: For Ethernet connections, it is highly recommended that the connection not be disconnected and re-connected between transactions. Doing so will have lower performance, and more importantly, each call to Connect() will consume a TCP connection in the Windows operating system. This TCP connection will not be fully released by the operating system until typically 2 minutes after Disconnect() is called. Therefore, it is possible to consume all available TCP connections by repeated calls to Connect()/Disconnect() and as a result be unable to re-connect over RMCLink or even adversely affect other applications running on the same PC.

Exceptions

Error Code	Description
rmcEOutOfMemory = 5	Out of memory.
rmcEAlreadyConnected = 1006	The link was already connected. To avoid this error, avoid calling Connect when the link is already connected. Use IsConnected if you are not sure if the connection is already made.
rmcESocketInternal = 1008	Internal socket error.
rmcESocketConnectionFailure = 1009	Unable to connect over TCP/IP to requested device.
rmcECancelled = 1010	Operation cancelled by call to CancelRequest.
rmcETimeout = 1011	Operation timed out.
rmcESocketHostNameNotIPv4 = 1012	Host name did not resolve to an IPv4 address.
rmcESocketHostNameNotResolved = 1013	Host name did not resolve.
rmcESocketGracefullyClosed = 1014	TCP/IP connection closed by remote device.
rmcESocketReadError = 1015	Connection error while waiting for response from the remote device.
rmcESocketInvReadLen = 1016	Connection error while waiting for response from the remote device.
rmcESocketWriteError = 1017	Connection error while sending request to the remote device.
rmcESocketInvWriteLen = 1018	Connection error while sending request to the remote device.
rmcEPortAccessDenied = 1019	Access to serial port denied. Verify not in use by another application.
rmcEPortNotFound = 1020	Serial port not found.
rmcESerialIOE = 1021	Serial IOE error.
rmcESerialFramingError = 1022	Serial framing error.
rmcESerialBreak = 1023	Serial Break error.
rmcESerialOverrun = 1024	Serial overrun.
rmcESerialRxOverrun = 1025	Serial receive overrun.
rmcESerialParityError = 1026	Serial parity error.
rmcESerialTxFull = 1027	Serial transmitter full.
rmcEConnectionBroken = 1028	Connection broken.
rmcEPartialWrite = 1029	Unable to send full request to the remote device.
rmcESocketHostnameInvalid = 1033	Invalid host name format.
rmcEWrongController = 1034	Remote device is the wrong controller type.
rmcEUSBNoDrivers = 1049	Unable to access RMC USB driver. Please ensure that the driver has been properly installed.
rmcEUSBDeviceNotFound = 1050	The controller with the specified DeviceId was not found on any USB port.
rmcEUSBInternal1 = 1051	Internal USB driver error.
rmcEUSBInternal2 = 1052	Internal USB driver error.
rmcEUSBOperationAborted = 1053	Unsuccessful transfer of data between the PC and the controller. Ensure that the physical connection between the PC and controller is still intact.
rmcEUSBDisconnected = 1054	The controller appears to have been disconnected from the USB port. Ensure that the physical connection between the PC and controller is still intact.
rmcEUSBUnknownFailure = 1055	The requested RMC is plugged into a USB port, but cannot be accessed. Ensure that no other applications are using this RMC. If the problem persists, try unplugging and re-plugging the USB cable to this controller and retry.
rmcEUSBInUse = 1056	The requested RMC is plugged into a USB port, but cannot be accessed. Ensure that no other applications are using this RMC. If the problem persists, try unplugging and re-plugging the USB cable to this controller and retry.
rmcEUSBNoSetupAPI = 1057	Unable to access operating system functionality for connecting to USB devices.

Example

The following code example illustrates the use of the Connect method.

Visual Basic 6 / VBA

Option Explicit
  
Public Sub Sample()
    ' Declare and create the RMCLinkServer COM object.
    Dim srv As New RMCLinkServer 
  
    ' Use our RMCLinkServer to create the correct type of RMCLink object.
    Dim rmc As RMCLink
    Set rmc = srv.CreateEthernetLink(dtRMC70, "192.168.0.22") 
  
    ' Establish the connection.
    rmc.Connect 
  
    ' Read F8:8 and F8:9 (Axis 0 Actual Position and Velocity)
    Dim data As Variant
    data = rmc.ReadFFile(fn70StatusAxis0, 8, 2)
    resultText = "Actual Position = " & data(0) & ", Actual Velocity = " & data(1) 
  
    ' Close the connection.
    rmc.Disconnect
End Sub

VBScript

Option Explicit
Dim srv, rmc, data
 
' First we need to create the RMCLinkServer COM object.
Set srv = CreateObject("RMCLink.RMCLinkServer")
 
' Use our RMCLinkServer to create the correct type of RMCLink object.
' NOTE: VBScript does not support enumerations, so we use the literal value (dtRMC70=2).
Set rmc = srv.CreateEthernetLink(2, "192.168.0.22")
 
' Establish the connection.
rmc.Connect
 
' Read F8:8 and F8:9 (Axis 0 Actual Position and Velocity)
data = rmc.ReadFFile_Script(8,8,2)
WScript.Echo "Actual Position = " & data(0) & ", Actual Velocity = " & data(1)
 
' Close the connection.
rmc.Disconnect

JScript

// First we need to create the RMCLinkServer COM object.
var srv = new ActiveXObject("RMCLink.RMCLinkServer");
 
// Use our RMCLinkServer to create the correct type of RMCLink object.
// NOTE: JScript does not support enumerations, so we use the literal value (dtRMC70=2).
var rmc = srv.CreateEthernetLink(2, "192.168.0.22");
 
// Establish the connection.
rmc.Connect();
 
// Read F8:8 and F8:9 (Axis 0 Actual Position and Velocity)
var data = rmc.ReadFFile_Script(8,8,2).toArray();
WScript.echo("Actual Position = " + data[0] + ", Actual Velocity = " + data[1]);
 
// Close the connection.
rmc.Disconnect();