/// <summary>
/// Open the underlying driver (VISA, Eiger, whatever)
///
/// If you need a shared session (VI_SHARED_LOCK), call Open() with exclusive==false then call LockSession.
/// </summary>
/// <param name="resource">the VISA resource descriptor. Ignored if simulated is true</param>
/// <param name="timeout">I/O timeout in ms ... not all drivers/sessions use this</param>
/// <param name="simulated">if true, no connection to hardware will be made</param>
/// <param name="exclusive">if true opens session exclusively (VI_EXCLUSIVE_LOCK). if false opens session with no lock (VI_NO_LOCK)</param>
public void Open(string resource, int timeout, bool simulated, bool exclusive)
{
// If already open, report an error...
if (IsSimulated || mSession != 0)
{
throw new IOException("VisaSession is already open");
}
mViDesc = resource;
mTimeout = timeout;
// Cache the resource descriptor -- may be used to open additional sessions to the same resource
ResourceDescriptor = resource;
Timeout = timeout;
mDefaultTimeout = timeout;
if (simulated)
{
// NOTE: if you want control of these values, use MockSession
IsSimulated = true;
mSlot = 1;
mModelCode = 0x1234;
mModelName = resource;
mSession = resource.GetHashCode();
return;
}
// Make sure cached values are cleared
mSlot = -1;
mModelCode = -1;
mModelName = string.Empty;
CheckStatus(AgVisa32.viOpen(
mResourceManager,
resource,
(exclusive) ? AgVisa32.VI_EXCLUSIVE_LOCK : AgVisa32.VI_NO_LOCK,
timeout,
out mSession));
// Cache the locked status
IsSessionLocked = exclusive;
// Use the supplied timeout as the default timeout for I/O operations
CheckStatus(AgVisa32.viSetAttribute(mSession, AgVisa32.VI_ATTR_TMO_VALUE, timeout));
// NOTE: DMA default settings ... For Agilent IOLS 16.3.16603 these are
// VI_ATTR_DMA_ALLOW_EN 0
// VI_ATTR_SRC_INCREMENT 1
// VI_ATTR_DEST_INCREMENT 1
// VI_AGATTR_DMA_WRITE_THRESHOLD 512
// VI_AGATTR_DMA_READ_THRESHOLD 48
// VI_AGATTR_DMA_CHANNEL -1
}
/// <summary>
/// Set the specified attribute
/// </summary>
/// <param name="attribute"></param>
/// <param name="value"></param>
/// <returns></returns>
public void SetSessionAttribute(int attribute, int value)
{
CheckStatus(AgVisa32.viSetAttribute(mSession, attribute, value));
}
