RMCLink.ReadFFile Method

Reads one or more floating-point (F) registers from the controller. This method cannot be used in VBScript or JScript; use the ReadFFile_Script method instead. ReadFFile is typically used to read floating-point registers from the RMC70, RMC150, or RMC200.

Syntax

Visual Basic (Declaration)

Function ReadFFile ( _

file As Long, _

element As Long, _

count As Long _

) As Variant

Visual Basic (Usage)

Dim instance As RMCLink

Dim file As Long

Dim element As Long

Dim count As Long

Dim returnValue As Variant

returnValue = instance.ReadFFile(file, element, count)

Parameters

file

File number of the first register to be read. See the RMCLink Register Reference for details.

element

Element number of the first register to be read. See the RMCLink Register Reference for details.

count

The number of registers to read.

Return Value

This variant will be filled with the data read from the controller. The variant data type will be a single-dimension 0-based array of Single elements. The length is determined by count.

Remarks

The only difference between ReadFFile_Script and ReadFFile is the format of the data returned in the Variant return value. For ReadFFile, the Variant holds a single-dimension 0-based array of Single elements. For ReadLFile_Script, the Variant holds a single-dimension 0-based array of Variant elements, and each Variant element in turn holds a Single. This extra layer of indirection is required by some scripting languages (VBScript and JScript, for example), but is other less efficient and should be avoided when ReadLFile is supported by your language.

Notice that all RMC100 registers are integers. Therefore, using this method to read data from the RMC100 will simply convert the values to floating point. For example, reading a value of 25 will be stored as a Single in the output array as 25.0.

For details on integer (L) and floating-point (F) registers and how to read from and write to both, see RMC100 Register Data Types or RMC70, RMC150, and RMC200 Register Data Types.

This method is synchronous, which means that it will not return until the read is completed, which may take several seconds. 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.

Exceptions

Error Code	Description
rmcEOutOfMemory = 5	Out of memory.
rmcEInvalidArg = 7	One of the file, element, or counts parameters are out of range.
rmcEDisconnecting = 1002	Link is being disconnected by another thread.
rmcEDisconnected = 1005	The link has not been connected.
rmcESocketInternal = 1008	Internal socket error.
rmcECancelled = 1010	Operation cancelled by call to CancelRequest.
rmcETimeout = 1011	Operation timed out.
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.
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.
rmcEBadAddress = 1032	Attempt to read beyond the end of a file.
rmcEUSBInternal1 = 1051	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.

Example

The following code example illustrates the use of the ReadFFile 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