Why no serial response?

[csi04]

Hi,

I have a simple labview application trying to communicate serially with a device. I have tried communicating with the device serially using C code. I am doing the exact thing using Labview but I do not receive any response from the device. I know for sure the device is receiving the initial packet that puts it (the device) in serial communication mode. I also know that the device is sending an ACK packet. I receive this in my C code but when I try in Labview no bytes are seen in receive buffer. I have attached my VI. Please let me know if you see something wrong.

Thanks,

Sharmila

[tbob]

The only thing I can see is that perhaps your device is expecting a different format.  By using type cast, you are converting the numbers into a binary representation string.  Maybe the device is expecting numerical characters, so maybe you should use Number to String functions instead of type cast.  If this is not so, I don't see anything else wrong.  Check to make sure your baud rate, stop bits, parity bit, etc. are correct.  You could use a loopback cable to make sure you are sending the correct data.  Remove your device and connect pins 2 and 3 together on the 9 pin connector.  This will send your tx data back into the com port.  You should then receive what you sent.

[Brian_Beal]

What is the device that you are trying to talk to? 

A couple of things to keep in mind.  Verify the correct, if any, termination character.  Also,  the timing between the write and read will not be consistant since you are using the Wait Until Next Multiple function.  You may want to put the Bytes at Port property node in a loop until it sees the 6 bytes, or times out.

[Dynamik]

Hi csi04,

It looks like you want to send 6 bytes, but you're sending 24 bytes, as you've initialized the array to be 6 - 32-bit-signed-ints! 🙂

(see the conversion at STX?)

Message Edited by Dynamik on 11-11-2005 02:16 AM