WinIOError on SerialPort on deployment machine only.

[Fr33dan]

Hi,

I've probably given more information than necessary but at this point I'm not sure what is relevant or not.

I have a program that has multiple classes on a single thread making calls to a static instance of SerialPort to communicate with testing hardware (via a Prologix GPIB card but I don't think that's relevant). This static SerialPort instance is managed by a PrologixGPIB class the devices use to interface with it.

This code has been working for months but last week I changed one of the classes to write a double that I called ToString on instead of the hard coded placeholder string. On my development machine this was no problem but on my deployment machine I get the error: "The I/O operation has been aborted because of either a thread exit or an application request."

Here is my SerialPort setup:

public PrologixGPIB(byte primaryAddress)
        {
            if (sp == null)
            {
                sp = new SerialPort();
 
                // COM port parameters
                ConfigAddress addr = Config.findAddress("GPIB_Controller.DeviceType", "PrologixGPIB");
                addr.attribute = "Tag";
                Log.writeLog(log, "Loading Configured Port");
                sp.PortName = Config.getValue(addr);
                sp.BaudRate = 115200;
                sp.DataBits = 8;
                sp.Parity = Parity.None;
                sp.StopBits = StopBits.One;
 
                // RTS/CTS handshaking
                sp.Handshake = Handshake.RequestToSend;
                sp.DtrEnable = true;
 
                sp.WriteTimeout = 10000;
                sp.ReadTimeout = 10000;
 
                // Error handling
                sp.DiscardNull = false;
                sp.ParityReplace = 0;
                sp.Open();
 
                // Sets the prologix GPIB to controller mode.
                sp.WriteLine("++mode 1");
            }
            this.address = primaryAddress;
 
            setAddress();
 
 
            Log.writeLog(log, "GPIB Configured");
        }
        ~PrologixGPIB()
        {
            if (sp != null)
            {
                sp.DiscardInBuffer();
                sp.DiscardOutBuffer();
                sp.Close();
                sp = null;
                Log.writeLog(log, "GPIB Closed");
            }
        }

Write method:

public override void write(string data)
        {
            try
            {
                setAddress();
                Log.writeLog(log, "Writing GPIB Command | " + data);
                string newData = data;
                foreach (char c in END_OF_LINE_CHARS)
                {
                    newData += c;
                }
                sp.DiscardInBuffer();
                sp.Write(newData);
            }
            catch (TimeoutException e)
            {
                throw new GPIBException("The GPIB write timed out | " + data,e);
            }
        }

Offending code:

public override void setGateTime(string time)
        {
            this.write("GATE" + time);
        }
 
        public override void setGateTime(double time)
        {
            this.setGateTime(time.ToString("##.###"));
        }

In my searching I've discovered that this error can be caused by having an improperly closed SerialPort but the error happens every time right after the computer is booted and the SerialPort hasn't been touched.

EDIT: Forgot to mention the dev machine is running Windows XP SP3 and the deployment machine is Windows 2000 SPwhatever the last was