CRMCLink::ReadFFile Method

Reads one or more floating-point (F) registers from the controller. Use ReadFFile to read floating-point registers from the RMC70, RMC150, or RMC200. Compare with ReadLFile.

Syntax

C++

HRESULT ReadFFile(

UINT file,

UINT element,

UINT count,

float* pData

);

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.

pData

Pointer to an array of float values with at least count elements. The register values that are read will be placed into this array.

Return Value

Returns S_OK on success. Otherwise, an error code is returned. Possible error codes are listed below.

Remarks

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 float 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.

Error Codes

Member Name	Description
E_OUTOFMEMORY	Out of memory.
E_INVALIDARG	One of the file, element, or count parameters are out of range.
RMCLINK_E_DISCONNECTING	Link is being disconnected by another thread.
RMCLINK_E_DISCONNECTED	The link has not been connected.
RMCLINK_E_SOCK_INTERNAL	Internal socket error.
RMCLINK_E_CANCELLED	Operation cancelled by call to CancelRequest.
RMCLINK_E_TIMEOUT	Operation timed out.
RMCLINK_E_SOCK_GRACEFUL_CLOSE	TCP/IP connection closed by remote device.
RMCLINK_E_SOCK_ERROR_RD	Connection error while waiting for response from the remote device.
RMCLINK_E_SOCK_INV_RD_LEN	Connection error while waiting for response from the remote device.
RMCLINK_E_SOCK_ERROR_WR	Connection error while sending request to the remote device.
RMCLINK_E_SOCK_INV_WR_LEN	Connection error while sending request to the remote device.
RMCLINK_E_CE_IOE	Serial IOE error.
RMCLINK_E_CE_FRAME	Serial framing error.
RMCLINK_E_CE_BREAK	Serial Break error.
RMCLINK_E_CE_OVERRUN	Serial overrun.
RMCLINK_E_CE_RXOVER	Serial receive overrun.
RMCLINK_E_CE_RXPARITY	Serial parity error.
RMCLINK_E_CE_TXFULL	Serial transmitter full.
RMCLINK_E_CONN_BROKEN	Connection broken.
RMCLINK_E_PARTIAL_WRITE	Unable to send full request to the remote device.
RMCLINK_E_BAD_ADDRESS	Attempt to read beyond the end of a file.
RMCLINK_E_USB_SETTIMEOUT	Internal USB driver error.
RMCLINK_E_USB_OP_ABORT	Unsuccessful transfer of data between the PC and the controller. Ensure that the physical connection between the PC and controller is still intact.
RMCLINK_E_USB_DISCONNECT	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.

C++

#include <windows.h>
#include <stdio.h>
#include "RMCLink.h"
 
void main()
{
    // In order to create COM objects, we must initialize the COM sub-system.
    ::CoInitialize(0);
 
    // Create a new RMCLink object.
    CRMCLink* pRMC = CRMCLink::CreateEthernetLink(CRMCLink::dtRMC70, _T("192.168.0.22"));
    if ( pRMC != NULL )
    {
        // Establish the connection.
        HRESULT hr = pRMC->Connect();
        if ( SUCCEEDED(hr) )
        {
            // Read F8:8 and F8:9 (Axis 0 Actual Position and Velocity)
            float afData[2];
            hr = pRMC->ReadFFile(CRMCLink::fn70StatusAxis0, 8, 2, afData);
            if ( SUCCEEDED(hr) )
            {
                printf("Actual Position = %.3f, Actual Velocity = %.3f\n",
                    afData[0], afData[1]);
            }
 
            // Close the connection.
            pRMC->Disconnect();
        }
 
        // Free the RMCLink object we created.
        delete pRMC;
    }
 
    // Release the COM sub-system.
    ::CoUninitialize();
}