Having problem with simple serial communication

[Anupam0354]

Hi,

I am a newbie in Labview. I was tryong to just communicate with a Omega thermocouple which has a RS232 interface and hooked up to my pc. I was using the basic serial communication vi provided in  the example. I validated the instrument using MAX and it was showing : Prot: COM1, Baud: 9600, Parity: none, Flow control: none, syop bits: 1.0.

In the vi: I was sending a input string, if everything was working fine, it should have returned the same thing in the read string, as far as I understood. What may be the problem with the communication as I am not getting anything in the read string?

Hope to hear from you soon.

Regards

Anupam

[Dennis_Knutson]

You could be sending an incorrect string, sending without the correct termination character, have a wrong serial cable, have the wrong com settings, or any number of other problems. There is nothing in MAX that validates a serial instrument so I have no idea about what you mean. All that MAX will show is the settings of the pc's serial port.

If you have the instrument's manual, attach that and provide the exact string that you are sending with the example. Using another terminal emulation program such as Hyperterminal is also recomended. If you have problems with that, you should be able to get help from the vendor. Success with the other program would also confirm that you have the correct type of cable and com settings.

[Anupam0354]

Hi,

Thank you very much for your reply. I understood what you said. I was in dilemma whether the MAX was validating the device settings or not. So, I need to have the manual of the instrument to find out the settings of the four parameters such as Baud rate, parity etc, right? If it doesn't have any of this information, can it be configured? & what is hyperterminal, is that a feature of LV?

Waiting for your reply.

Regards

Anupam

[Dennis_Knutson]

If the manual does not have this information, contact the vendor.

Hyperterminal is a terminal emulation program that up until Vista, was included with every version of windows (Accessories>Communication>Hyperterminal). There are many free terminal terminal emulation programs (i.e. TerraTerm) available if you are using Vista or Windows7.

[Anupam0354]

Hello,

Thank you for your reply. Sorry for being late. I was busy with xams. I tried to find the parameters for Omega HH506R & have them now. I am using basic serial communication vi to communicate using the parameters. But there seems to be a problem. The wrrite operation probably operating correctly as there is a "click" sound from the thermometer while I am running it. But the reading string is not showing  anything. I have not been able  to solve this problem. Do you have any more suggestions? It'll be pretty helpful.

Regards

Anupam

[Dennis_Knutson]

Attach the manual and provide the exact string you are sending.

[Anupam0354]

Hi Dennis,

Thank  you very much for your reply.

Actually, which I got is the file attached which contains the parameters. The string I am sending is the one that is already in the serial  communicatio vi. I actually didn't get your point. Do I need to specify a certain command for the thermometer to understand? There must be some byte reading which it is reading if it is running the read string. It shows 0 in that window. 

Regards

Anupam

[Anupam0354]

Hi Dennis,

Thank  you very much for your reply.

Actually, which I got is the file attached which contains the parameters. The string I am sending is the one that is already in the serial  communicatio vi. I actually didn't get your point. Do I need to specify a certain command for the thermometer to understand? There must be some byte reading which it is reading if it is running the read string. It shows 0 in that window. 

Regards

Anupam

[Anupam0354]

Hello,

Again, do I need to set up the delay time for the reading string to be received? It is set as 500 ms.

Regards

Anupam

[Dennis_Knutson]

You can't just send whatever you feel like. You can only send commands that the instrument understand. These are listed in the manual, like 'A' to start sending data. Did you read any of it?