How to calculate Baudrate and Write-Readtimeouts?

Sascha B

Hello again :)

I recieve many code error from my device so I want to check if the timeouts are right.
This is what I send:

02 39 39 30 31 30 34 30 31 03 30 37 0D 0A

And this is what I recieve:

02 30 30 30 31 30 20 32 30 2B 32 31 35 30 33 2B 32 32 32 38 33 2B 32 33 36 32 33 03 30 31 0D 0A 02 30 30 30 31 30 20 32 30 2B 32 31 35 30 33 2B 32 32 32 38 33 2B 32 33 36 32 33 03 30 31 0D 0A

02 30 30 30 31 30 20 32 30 2B 32 31 35 30 33 2B 32 32 32 38 33 2B 32 33 36 32 33 03 30 31 0D 0A
These are my configurations:

comport.BaudRate = 9600;

comport.DataBits = 7;

comport.Parity = Parity.Even;

comport.Handshake = Handshake.XOnXOff;

comport.RtsEnable = true;

comport.ReadTimeout = 500;

comport.WriteTimeout = 500;

comport.PortName = portname;

How can I calculate if my timeouts are correct?

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sascha B14y ago
I used the handshaking from the device manual. So it has to be correct :)
Sam Hobbs14y ago
Before discarding hardware that did not function, I suggest checking to ensure the handshaking is used properly. Handshaking is the solution for data that is "being transmitted spasmodically". Right?
Sascha B14y ago
Thanks for the reply.
I tried it also with 1000 and 1500 and above but nothing changed.
Then I took an othe adapter :D And it works! The one I used before was a passive USB2Com Adapter by Logilink. It's in the trash now.
Now I use the PA088 from Targus. Works very well.
But for those who don't know how to check if the recieved data is complete I think I got the answer now:

private void handler()
{
while (true)
{
ComWork.getData(); // Sending Command to get data from Device
this.Invoke(new delaction(action)); // Explain it a second
System.Threading.Thread.Sleep(180); // Just a timebuffer so the device is not stressed out
}
}

private void action()
{
if (ComWork.ready) // In ComWork I check if my total recieved Data Length is greater or equal my espected Length. If so ready is true!
{
          ComWork.ready = false, // Setting it to false so a fresh new value can be recieved
          //Check if recieved coe is valid and proceed
          [...]
            }
Vulpes14y ago
Well, the timeouts you're using (500 ms) are the defaults for the Win32 Communications API and so should certainly be long enough for most purposes.

However, setting timeouts is not an exact science. Clearly, they need to be long enough to send or receive all the data in a single transmission which at 9600 kbits/sec is certainly the case here but, if the data is being transmitted spasmodically, you need to allow for the delay(s).

If you're having problems and you suspect the timeouts may be to blame, then I'd see if it makes any difference if you double them.