Bad Reading from the Serial Port

[Prachie]

Hello, 

I am trying to connect a Thermo Orion 420A pH metere through a RS232 cable. I tweaked the Basic serial write and read vi little bit because it wasn't reading anything from the port. Now, it is reading but, it is reading all 0s. I am not quite sure what the problem is. I have tried checking the COM ports and baud rate with the configuration of the device. Everything seems to match. Anyone who had this problem before have any suggestions for me? 

Thanks 

Prachie 

[Albert.Geven]

maybe you have to send a command first, to get the data on the line?

[Prachie]

I am still learning how to use labview. Could you please explain me more what do you mean by write a command to the line? What kind of command would that be? Is it of the form "*IDN?\r\n" ? What does this mean? 

Thanks 

Prachie

[Dennis_Knutson]

It really has nothing to do with LabVIEW. It has to do with understanding the manual for the instrument. You can't just randomly start writing code. You did not attach the manual so no one can tell what, if any command, the instrument requires in order to send data.

No, the command would not be *IDN?. That is not listed in the manual, is it?

Even though there may be something written to a file, you really have no idea if anything is actually being read. Your code will create 0's with no data there. Did you actually see the number of bytes be greater than 0.

[Prachie]

I didn't think that it would be IDN, but I just wanted to make sure. You mean number of bytes read? Yes, in the excel file, we read 0s about 20 times. Here is the manual(our instrument is Thermo Orion 420A) : 

[Dennis_Knutson]

Have you read it? It does not list your model as having remote control ability.

[Prachie]

I thought it did. On page 62 of the manual, it says

"The Orion 410Aplus and 420Aplus can send information to a printer or computer using the RS232 port. "  It also gives the configuration for the RS232 cable. 

[Dennis_Knutson]

Yes, by manually pressing a button on the instrument.