RMCLink.ReadBitField Method

Reads a bit field (range of bits) from an integer (L) register in the RMC, and converts the binary value of the bits to a long integer. ReadBitField is typically used to read the value of a multiple-bit parameter in the RMC70, RMC150, or RMC200.

Syntax

Visual Basic (Declaration)

Function ReadBitField ( _

file As Long, _

element As Long, _

fieldStart As Long, _

fieldLen As Long _

) As Long

Visual Basic (Usage)

Dim instance As RMCLink

Dim file As Long

Dim element As Long

Dim fieldStart As Long

Dim fieldLen As Long

Dim returnValue As Long

returnValue = instance.ReadBitField(file, element, fieldStart, fieldLen)

Parameters

file

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

element

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

fieldStart

Number of the least significant bit (0-31) of the register's bit field. Bits are numbered from least to most significant.

fieldLen

Total number of bits in the bit field (1-32).

Return Value

The value of the bit field is returned.

Remarks

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, fieldStart, or fieldLen 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 ReadBitField 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 bits 10-11 of L8:0 (Axis 0 Target State bits A and B)
    Dim Value As Long
    Value = rmc.ReadBitField(fn70StatusAxis0, 0, 10, 2)
    resultText = "Target State = " & Value
 
    ' Close the connection.
    rmc.Disconnect
End Sub

VBScript

Option Explicit
Dim srv, rmc, value
 
' 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 bits 10-11 of L8:0 (Axis 0 Target State bits A and B)
value = rmc.ReadBitField(8,0,10,2)
WScript.Echo "Target State = " & value
 
' 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 bits 10-11 of L8:0 (Axis 0 Target State bits A and B)
var value = rmc.ReadBitField(8,0,10,2);
WScript.echo("Target State = " + value);
 
// Close the connection.
rmc.Disconnect();