PDA COM port write problem

[ohw313]

Hello,

I am working on a rather interesting project that is started giving me headaches.

I have a LABVIEW application that controls a DUMB RS232 device. Works Great.

Just rewrote it for LABVIEW PDA using Bluetooth(Via a FREE2MOVE bluetooth/COM port converter with an HP2210 PDA). After a little battle , everything works fine(Reading data, Writing data) except for 1 function. In order to get the device into CONFIG mode I must send the same command twice within 100ms. This works fine on the PC version but when implemented on the PDA version the device will not go into CONFIG mode. It expects the same command(TWO BYTES) twice within 100ms with nothing inbetween. On the PC I just send the two BYTES(169 and 0), wait 20ms, then send it again
and it works. I read the manual of the RS232 device and it says that NO other commands may be send between the two Commands. I have noticed that in LABVIEW PDA serial comms that everytime your use the standard WRITE VI command it has an OPEN PORT function in the VI. I know this is just a virtual port but could this be sending anything that might be causing my device to ignore the second command? I have tried sending 4 bytes at one time but the RS232 device does not like this either.

Any ideas...please... 🙂

Would appreciate any ideas.

Jurgen

[SVences]

Hello!

I don�t think the Open Serial Driver.VI sends anything to the port that might be causing your device to ignore the second command. However, if you are using the Serial Port Write.VI two times in a row, you are opening a session to the same resource twice, which could be the reason why your program is hanging.

Go into the Serial Port Write.VI and try adding the Close Serial Driver.VI outside the case structure. This way, the next time you call the Serial Port Write function, the original session will be already closed and you can open a new one.

Hope this helps!