/// <summary>
/// Writes calibration data to an instrument.
/// </summary>
/// <param name="appSettings">ApplicationSettings object.</param>
/// <param name="gpibAddress">GPIB address of instrument.</param>
/// <param name="sramData">256 byte array containing data to write to instrument SRAM.</param>
static void WriteCalibration(ApplicationSettings appSettings, int gpibAddress, byte[] sramData)
{
// Check for valid data buffer
if (sramData == null || sramData.Length != 256)
{
throw new ArgumentException("SRAM data buffer must contain 256 bytes.", "sramData");
}
// Connect to GPIB adapter
GPIBConnection gpibConn = new GPIBConnection(appSettings.SerialPortName,
appSettings.SerialBaudRate, appSettings.SerialDataBits,
appSettings.SerialParity, appSettings.SerialStopBits,
appSettings.SerialFlowControl)
{
Timeout = appSettings.GPIBAdapterTimeout,
GPIBAdapterVersionString = appSettings.GPIBAdapterVersionString,
GPIBAddress = gpibAddress
};
gpibConn.Connect();
try
{
// Test instrument communications
string cmdResult = gpibConn.QueryInstrument("S");
if (cmdResult != "0" && cmdResult != "1")
{
throw new ApplicationException("Could not communicate with instrument.");
}
// Display "WRITING CAL" on instrument
gpibConn.QueryInstrument("D2WRITING CAL", false);
gpibConn.QueryInstrumentBinary(new byte[] { 0x1b, 0x0d }, 0); // Terminate D2 command
// Setup command buffer to write calibration data.
//
// The first byte 'X' is the write SRAM command.
//
// The second and forth bytes are the ESC (ASCII 27) character
// used to escape the following byte in order to ensure it gets
// sent to the instrument and not consumed by the GPIB adapter.
//
// The third byte is the SRAM address to be written.
//
// The fifth byte is the SRAM data to be written.
//
// Notes:
// - SRAM is 256 x 4 (256 4-bit nibbles).
//
// - X<addr><val> command is used to write SRAM nibbles where
// <addr> is an SRAM address from 0-255 and <val> is the data
// to be written.
//
// - The instrument ignores the upper four bits of the data byte.
// For example, to write the value 0x5 to the instrument,
// sending a data byte of 0x05 or 0x45 ('E') are both equivalent.
//
// - Only escaping CR, LF, ESC and '+' is required, but all
// characters are escaped for simplicity.
byte[] writeCmdBytes = new byte[5];
writeCmdBytes[0] = Convert.ToByte('X');
writeCmdBytes[1] = 0x1b;
writeCmdBytes[2] = 0x00;
writeCmdBytes[3] = 0x1b;
writeCmdBytes[4] = 0x00;
// Setup command buffer to read SRAM
byte[] readCmdBytes = new byte[3];
readCmdBytes[0] = Convert.ToByte('W');
readCmdBytes[1] = 0x1b;
readCmdBytes[2] = 0x00;
// Write all 256 nibbles of SRAM
byte[] sramBytes = new byte[256];
for (int i = 0; i < 256; i++)
{
// Send command to instrument
writeCmdBytes[2] = (byte)i;
writeCmdBytes[4] = sramData[i];
gpibConn.QueryInstrumentBinary(writeCmdBytes, 0);
// Read value back for verification of successful write
readCmdBytes[2] = (byte)i;
byte[] recvByte = gpibConn.QueryInstrumentBinary(readCmdBytes, 1);
// Verify correct nibble was read back from instrument
if (recvByte == null || recvByte.Length != 1 ||
(recvByte[0] & 0x0f) != (sramData[i] & 0x0f))
{
throw new ApplicationException("Failed while verifying calibration data in instrument SRAM.");
}
}
// Return instrument to normal display
gpibConn.QueryInstrument("D1", false);
}
finally
{
// Disconnect from GPIB adapter
gpibConn.Disconnect();
}
}
/// <summary>
/// Reads calibration data from an instrument.
/// </summary>
/// <param name="appSettings">ApplicationSettings object.</param>
/// <param name="gpibAddress">GPIB address of instrument.</param>
/// <returns>256 byte array containing instrument SRAM data.</returns>
static byte[] ReadCalibration(ApplicationSettings appSettings, int gpibAddress)
{
// Connect to GPIB adapter
GPIBConnection gpibConn = new GPIBConnection(appSettings.SerialPortName,
appSettings.SerialBaudRate, appSettings.SerialDataBits,
appSettings.SerialParity, appSettings.SerialStopBits,
appSettings.SerialFlowControl)
{
Timeout = appSettings.GPIBAdapterTimeout,
GPIBAdapterVersionString = appSettings.GPIBAdapterVersionString,
GPIBAddress = gpibAddress
};
gpibConn.Connect();
byte[] sramBytes;
try
{
// Test instrument communications
string cmdResult = gpibConn.QueryInstrument("S");
if (cmdResult != "0" && cmdResult != "1")
{
throw new ApplicationException("Could not communicate with instrument.");
}
// Display "READING CAL" on instrument
gpibConn.QueryInstrument("D2READING CAL", false);
gpibConn.QueryInstrumentBinary(new byte[] { 0x1b, 0x0d }, 0); // Terminate D2 command
// Setup command buffer to read calibration data.
//
// The first byte 'W' is the read SRAM command.
//
// The second byte is the ESC (ASCII 27) character used to escape
// the following byte in order to ensure it gets sent to the
// instrument and not consumed by the GPIB adapter.
//
// The third byte is the SRAM address to be read.
//
// Notes:
// - SRAM is 256 x 4 (256 4-bit nibbles).
//
// - W<addr> command is used to read SRAM nibbles where <addr>
// is an SRAM address from 0-255.
//
// - Nibbles are returned from the instrument with 0x40 added to
// them to make them human readable ASCII.
// For example, if the nibble value is 0x5, then 0x45 or 'E'
// is the byte returned.
//
// - Only escaping CR, LF, ESC and '+' is required, but all
// characters are escaped for simplicity.
byte[] cmdBytes = new byte[3];
cmdBytes[0] = Convert.ToByte('W');
cmdBytes[1] = 0x1b;
cmdBytes[2] = 0x00;
// Read all 256 nibbles of SRAM
sramBytes = new byte[256];
for (int i = 0; i < 256; i++)
{
// Send command to instrument
cmdBytes[2] = (byte)i;
byte[] recvByte = gpibConn.QueryInstrumentBinary(cmdBytes, 1);
if (recvByte == null || recvByte.Length != 1)
{
throw new ApplicationException("Failed while reading calibration data from instrument SRAM.");
}
// Copy received byte to buffer
sramBytes[i] = recvByte[0];
}
// Return instrument to normal display
gpibConn.QueryInstrument("D1", false);
}
finally
{
// Disconnect from GPIB adapter
gpibConn.Disconnect();
}
return(sramBytes);
}