private ScpiResult DoWriteToInstrument(string command)
{
var result = new ScpiResult();
if (mVi == VisaInteropConstant.VI_NULL)
{
return(result);
}
try
{
int numRead = 0;
byte[] buf = Encoding.ASCII.GetBytes($"{command}{DefaultEolSequence}");
int status = VisaInterop.viWrite(mVi, buf, buf.Length, ref numRead);
if (VisaInteropUtil.Failed(status))
{
result.Message = VisaInteropUtil.GetStatusDescription(mVi, status);
}
else
{
result.Succeed = true;
}
}
finally
{
}
return(result);
}
private ScpiResult SetTimeout(int vi, int timeout)
{
var result = new ScpiResult();
int attr = VisaInteropAttribute.VI_ATTR_TMO_VALUE;
int status = VisaInterop.viSetAttribute(vi, attr, timeout);
if (VisaInteropUtil.Failed(status))
{
result.Succeed = false;
result.Message = VisaInteropUtil.GetStatusDescription(vi, status);
}
else
{
result.Succeed = true;
}
return(result);
}
private static ScpiResult viOpen(string address, int viDefRm, out int vi)
{
vi = -1;
var result = new ScpiResult();
var status = VisaInterop.viOpen(viDefRm, address, VisaInteropConstant.VI_NO_LOCK, DefaultConnectTimeout, ref vi);
if (VisaInteropUtil.Failed(status))
{
result.Succeed = false;
result.Message = VisaInteropUtil.GetStatusDescription(viDefRm, status);
}
else
{
result.Succeed = true;
}
return(result);
}
private static ScpiResult viOpenDefaultRm(out int viDefRm)
{
var result = new ScpiResult();
viDefRm = -1;
int status = VisaInterop.viOpenDefaultRM(ref viDefRm);
if (VisaInteropUtil.Failed(status))
{
result.Succeed = false;
result.Message = VisaInteropUtil.GetStatusDescription(viDefRm, status);
}
else
{
result.Succeed = true;
}
return(result);
}
private static ScpiResult enableTermination(int vi)
{
var result = new ScpiResult();
// Enable termination character if required for this session type (serial and socket).
if (IsTermCharTerminationRequired(vi))
{
var status = VisaInterop.viSetAttribute(vi, VisaInteropAttribute.VI_ATTR_TERMCHAR_EN, 1);
if (VisaInteropUtil.Failed(status))
{
result.Succeed = false;
result.Message = VisaInteropUtil.GetStatusDescription(vi, status);
}
else
{
result.Succeed = true;
}
}
return(result);
}
private ScpiResult Connect(string address)
{
int viDefRm = -1;
var openDefaultRm = viOpenDefaultRm(out viDefRm);
if (!openDefaultRm.Succeed)
{
return(openDefaultRm);
}
mViDefRm = viDefRm;
int vi = -1;
var viOpenResult = viOpen(address, viDefRm, out vi);
if (!viOpenResult.Succeed)
{
return(viOpenResult);
}
mVi = vi;
var terminationResult = enableTermination(vi);
if (!terminationResult.Succeed)
{
return(terminationResult);
}
var setTimeoutResult = SetTimeout(vi, DefaultCommunicationTimeout);
if (!setTimeoutResult.Succeed)
{
return(setTimeoutResult);
}
var result = new ScpiResult();
result.Succeed = true;
return(result);
}
public ScpiResult SendReadCommand(string address, string command)
{
var connectResult = Connect(address);
if (!connectResult.Succeed)
{
return(connectResult);
}
var result = new ScpiResult();
var writeResult = DoWriteToInstrument(command);
if (writeResult.Succeed)
{
result = ReadString();
}
else
{
result.Message = writeResult.Message;
}
Disconnect();
return(result);
}
private ScpiResult ReadString()
{
var result = new ScpiResult();
var response = new List <string>();
if (mVi == VisaInteropConstant.VI_NULL)
{
return(result);
}
int status;
// StringBuilder strBld = new StringBuilder(mReadBufferSize);
try
{
byte[] buf = new byte[DefaultReadBufferSize];
int numRead;
int binBlockBytesToRead = 0;
bool isBinBlock = false;
bool checkedForBinBlock = false;
while (true)
{
// Read up to a full buffer's worth of data
numRead = 0;
status = VisaInterop.viRead(mVi, buf, buf.Length, ref numRead);
if (VisaInteropUtil.Failed(status))
{
result.Message = VisaInteropUtil.GetStatusDescription(mVi, status);
}
// shiqiang: copy data to new allocaed byte array and add byte array to response
byte[] readBuf = new byte[numRead];
for (int i = 0; i < numRead; i++)
{
readBuf[i] = buf[i];
}
var read = Encoding.ASCII.GetString(readBuf);
response.Add($"{read}{Environment.NewLine}");
//Append data in buffer the rest of the data that's been read
//string str = Encoding.ASCII.GetString(buf, 0, numRead);
//strBld.Append(str);
// On first block of data read, determine if we are dealing with an IEEE 488.2
// definite length block.
if (!checkedForBinBlock)
{
isBinBlock = IsValid4882BlockHeader(readBuf, out binBlockBytesToRead);
checkedForBinBlock = true;
}
// Handle 488.2 definite length binblocks by attempting to read all the data
// regardless of term chars.
if (isBinBlock)
{
binBlockBytesToRead -= numRead;
}
// Determine whether or not there is more data to read
if (status == VisaInteropConstant.VI_SUCCESS)
{
result.Succeed = true;
// VI_SUCCESS indicates END was received - no more data.
break;
}
else if (status == VisaInteropStatus.VI_SUCCESS_MAX_CNT)
{
// VI_SUCCESS_MAX_CNT indicates we filled the buffer and
// there is more data (otherwise we would have gotten either
// VI_SUCCESS or VI_SUCCESS_TERM_CHAR).
continue;
}
else if (status == VisaInteropStatus.VI_SUCCESS_TERM_CHAR)
{
if (isBinBlock && (binBlockBytesToRead > 0))
{
// If we are processing a binary block, read until we've read
// all the bytes indicated in the header. Since the data might
// contain term chars, don't end prematurely on those.
continue;
}
else
{
result.Succeed = true;
// For serial and socket, VI_SUCCESS_TERM_CHAR indicates no more data.
break;
}
}
}
}
// shiqiag: catch possible exceptions include OutOfMemoryException
catch (Exception ex)
{
result.Message = ex.Message;
}
if (result.Succeed)
{
var builder = new StringBuilder();
foreach (var item in response)
{
builder.Append(item);
}
result.Message = builder.ToString();
}
return(result);
}
