Serial Port Problem with Lookut 5.0

[JPhillips]

I use 4 serial ports to transmit my data from the field to the server computer and I am using the National Instruments USB-232 4 port serial interface. 2 of these ports have been recently locking up at different times and this is indicated by the LED on the interface turning red.

The only way I can get them to start working again is to reboot the computer.

Does anyone have an idea of what would cause the ports to lock up?

Thanks.

Jason

[TheScott]

Jason,

From the NI-Serial manual (page 7-17 in the version I found here) it seems that the red light on a port indicates that the port is open but there are no signals (ie nothing connected to the port). The port being open would certainly impair your ability to open it in another application since only one application can have it open at a time. So, in order to "unlock" your port, you need to close it in the original application that opened it.

I experimented with my USB-232 device and it seems that it's looking any one of a number of pins (like DSR, DTR, RxD, TxD) to be connected to a mark or space voltage before it changes the port LED to green, just in case you were wondering what the difference wa
s. In any case, if the LED is lit at all, then the port is open.

Scott

[JPhillips]

Scott,

So, what are you saying is that while I have Lookout polling through that port another app is opening the port?

I could somewhat believe that could happen but because I can get Lookout to start polling through the port again by closing Lookout, going into the control panel, disabling the port, then re-enabling the port, and opening Lookout, it seems that another app is not causing this.

Any ideas?

Thanks for the response.

Jason

[TheScott]

So is the LED green while everything is working normally, then it changes to red and everything stops working? If this is the case, then I would check your cabling. If the LED remains lit (red or green) after Lookout is closed, then you might want to make sure that Lookout is closing the serial port correctly. Unfortunately, I don't have much Lookout experience if this is the issue; you might try the Lookout discussion forum.

Scott

[JPhillips]

Yes, the LED is blinking green and yellow when everything is working but then turns red and that is when all communication through the port stops. We have checked our cables before and they were fine but we will check them again to make sure. If they check out OK I will check with NI about Lookout closing the serial port correctly.

Thanks for your insight.

Jason

[JPhillips]

Scott,

I just spoke with my technician and he told me that the LED "blinks" red rather than being solid red when we lose data transfer through the port. I saw in the manual that this reflects a FIFO Overrun, parity error, or framing error.

Would you know what I can do to prevent these errors or the FIFO Overrun?

Jason