problems with read long string from serial port

[EdbO]

Hello,

I got problems to read a long string of 101 bytes from the serial port. Most times I read the 101 bytes but sometimes it will read 76 bytes or less, so the data will be infected with wrong values

With reading short strings of 8 bytes I don't have this problem. I use the same vi to read the 101 bytes and I'm using labview 8.0 on windows XP. Is there a workaround for this?

Eddy

[Yukee]

How many byte count you set ?

[tst]

A likely candidate is the timeout - if your timeout is too short, you won't always get all your data. Another potential problem is if you're using a termination character. Both can be changed by using the VISA Configure Serial Port VI.

If this didn't help, you should post your code, with more details about the problem.

[EdbO]

Hello,

Between write and read I have 500 ms. IMHO this have to be enough. I have the vi attached. Please take a look.

Thanks

Eddy

[Yukee]

Hi,

       Can you save the sample as LV7.1

帖子被Yukee在12-06-2005 04:13 AM时编辑过了

[EdbO]

Hello,

Saved as 7.1

Eddy

[Yukee]

Hi,

    I have modified your sample simply. see it and have a try.

[EdbO]

Hello,

Thanks for your time, but it doesn't work

The return count is zero. After more cycles it's still zero.

Eddy

[tbob]

Here are some things to try:

Are you using flow control? (RTS/CTS or XON/XOFF).  If not, try using flow control.  Assert RTS, and set flow control to RTS/CTS on the init vi.

Make sure your baud rate, stop bits, parity are correct.

Disable the terminating character in the init vi if transferring binary data.

Increase wait time between writing and reading.

Try reading twice at the end to see if more data is coming.

Hope these suggestions help.