/// <summary>
/// Establish a connection to the DMM.
/// </summary>
/// <param name="portName">The name of the serial port to use.</param>
private void Connect(string portName)
{
// Validate the port name
if (string.IsNullOrWhiteSpace(portName))
{
return;
}
// Initialize the multimeter object
meter = new Multimeter(portName);
// Set the alive flag and clear the blank counter
isAlive = true;
blankCount = 0;
// Try to establish the connection
Exception error = meter.Connect();
if (error != null)
{
// If there was any error, exit, as there is no recovery from this
MessageBox.Show(string.Format(Language.ConnectionErrorText, portName, error.Message),
Language.ConnectionErrorTitle, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
ChangeUI(false);
return;
}
// Change the UI
ChangeUI(true);
// Start the timer
acquisitionTimer.Start();
}
private void acquisitionTimer_Tick(object sender, EventArgs e)
{
// Make sure that the state and meter objects are valid
if (!isConnected || meter == null || !meter.IsConnected)
{
// Disconnect and return, if not
Disconnect();
return;
}
// Stop the timer
acquisitionTimer.Stop();
// Handle pause mode
if (isPaused)
{
// Discard the samples, start the timer again and continue
meter.Flush();
acquisitionTimer.Start();
return;
}
// Check, if the maximum duration of missed screen updates has been exceeded
if ((blankCount - 1) * acquisitionTimer.Interval >= 1000)
{
// Clear the readout, bargraph and alive flag after a certain number of missed updates
isAlive = false;
UpdateStatusLabels();
ClearReadout();
ClearBargraph();
}
// Always update the blank count (it will be reset if there was a successful update)
blankCount++;
// Handle pending timer updates
if (isTimerUpdatePending)
{
UpdateTimer();
}
// Read all available packets
Packet sample = new Packet();
bool success = false;
while (meter.IsAvailable)
{
if (!meter.Receive(out sample))
{
// Update the blank screen count
blankCount++;
// And turn the sampling on again
acquisitionTimer.Start();
return;
}
// Skip invalid packets
if (!sample.ChecksumValid)
{
continue;
}
// Set the success flag
success = true;
}
// Check, if the reception was successful
if (!success)
{
// Start the timer again
acquisitionTimer.Start();
return;
}
// Clear the blank screen count and set the alive flag after a successful reception
blankCount = 0;
if (!isAlive)
{
isAlive = true;
UpdateStatusLabels();
}
// Handle regular display
// Set the mode label accordingly first
bool validMode = true;
bool valueMode = true;
switch (sample.Mode)
{
case Mode.Ampere:
modeLabel.Text = Language.ModeCurrent;
break;
case Mode.AmpereMicro:
modeLabel.Text = Language.ModeCurrent;
break;
case Mode.AmpereMilli:
modeLabel.Text = Language.ModeCurrent;
break;
case Mode.ContinuityOhm:
modeLabel.Text = Language.ModeContinuity;
break;
case Mode.DiodeVolt:
modeLabel.Text = Language.ModeDiode;
break;
case Mode.ResistanceOhm:
modeLabel.Text = Language.ModeResistance;
break;
case Mode.VoltAC:
modeLabel.Text = Language.ModeVoltageAC;
break;
case Mode.VoltDC:
modeLabel.Text = Language.ModeVoltageDC;
break;
case Mode.Squarewave:
modeLabel.Text = Language.ModeSquarewave;
valueMode = false;
break;
default:
modeLabel.Text = Language.ModeUnknown;
valueMode = false;
validMode = false;
break;
}
// Compare the last range with the current one
if (lastMode != sample.Mode)
{
ClearStatistics();
lastMode = sample.Mode;
}
// Allocate variables for the number parsing
bool negative = false;
int integer = 0, fractional = 0, exponent = 0, precision = 0;
char unit = '\0', unitPrefix = '\0';
// Attempt to parse the number
if (validMode && valueMode)
{
validMode = Multimeter.Parse(sample, out negative, out integer, out fractional, out exponent, out precision, out unit, out unitPrefix);
}
// Check, if the mode is invalid or that the number is OL
bool overloaded = Multimeter.IsOverloaded(sample);
if (overloaded && valueMode) // Overload
{
// Update the value and unit labels
valueLabel.Text = "OL";
unitLabel.Text = unit.ToString();
// Fill the bargraph
FillBargraph();
}
else if (!validMode || !valueMode)
{
// No valid mode
valueLabel.Text = "";
unitLabel.Text = "";
// Clear the bargraph
ClearBargraph();
// Cancel and skip the rest
acquisitionTimer.Start();
return;
}
else
{
// Just format the value according to the precision
valueLabel.Text = precision < 1 ? integer.ToString() :
string.Format("{0}{1}.{2:D" + precision.ToString() + "}", negative ? "-" : "", integer, fractional);
// Also update the unit label
unitLabel.Text = unitPrefix == '\0' ? unit.ToString() : string.Format("{0}{1}", unitPrefix, unit);
}
// Update the UI
if (!overloaded)
{
// Update the bargraph
bargraphBar.Minimum = 0;
bargraphBar.Maximum = sample.Value < 0 ? Math.Abs(Multimeter.RangeMin(sample.Mode, sample.Range)) : Multimeter.RangeMax(sample.Mode, sample.Range);
bargraphBar.Value = Math.Abs(sample.Value);
// Calculate the double value
double currentValue = Math.Pow(10, exponent) * (integer + (fractional * Math.Pow(10, -precision)));
if (negative)
{
currentValue = -currentValue;
}
// Update the min statistics
if (resetStatistics || minValue > currentValue)
{
minValue = currentValue;
minValueLabel.Text = valueLabel.Text + unitLabel.Text;
}
// Update the max statistics
if (resetStatistics || maxValue < currentValue)
{
maxValue = currentValue;
maxValueLabel.Text = valueLabel.Text + unitLabel.Text;
}
// Unset the statistics flag
if (resetStatistics)
{
resetStatistics = false;
}
}
// Handle record mode only for valid value modes
if (isRecording)
{
// Calculate the offset in seconds
TimeSpan delta = sample.ReceptionTime - recordingStart;
// Assemble the line, e.g.: 2022/04/29 10:25:03,4.32,12.34E-3,V
// Start with date and time
recordingBuffer.AppendFormat("{0} {1}", sample.ReceptionTime.ToLongDateString(), sample.ReceptionTime.ToLongTimeString());
// Followed by the delimiter
recordingBuffer.Append(GetCSVDelimiter());
// Continue with the time offset
recordingBuffer.AppendFormat(new NumberFormatInfo()
{
NumberDecimalSeparator = GetCSVFractionalSeparator().ToString(), NumberDecimalDigits = 2
},
"{0:E}", delta.TotalSeconds);
// Followed by the delimiter
recordingBuffer.Append(GetCSVDelimiter());
// Followed by the value
if (overloaded) // Overload
{
recordingBuffer.Append("OL");
}
else if (precision < 1) // Integer value
{
recordingBuffer.AppendFormat("{0}E{1}", integer, exponent);
}
else // Fixed point value
{
recordingBuffer.AppendFormat("{0}{1}{2}{3:D" + precision.ToString() + "}E{4}", negative ? "-" : "", integer,
GetCSVFractionalSeparator(), fractional, exponent);
}
// Followed by the delimiter
recordingBuffer.Append(GetCSVDelimiter());
// Followed by the unit
recordingBuffer.Append(unit);
// And a final line break
recordingBuffer.AppendLine();
// Update the running for label and increment the sample counter
recordingCount++;
UpdateStatusLabels();
}
// Start the timer again
acquisitionTimer.Start();
}