Re : VISA write buffer

[kdm7]

How do figure out what hex values to write in the write buffer?

[Dennis_Knutson]

How do you know that you have to write hex values? What does the manual say? What is the instrument?

[JB]

To communicate with a device ? See its protocol.

PS : Your question is much too vague to expect a detailed answer.

[kdm7]

I am documenting a VI and I saw the hex values in write buffer.

Communication is through the internet.

I dont know what device is used. What possible devices can be used?

This VI is for monitoring and display (no acquisition).

[Dennis_Knutson]

This is just the wrong place to be asking what instrument is connected on your network. If there is no one at your company that can provide this information, run away now. If you cannot determine it yourself, then you lack basic knowledge of instrumentation and you should ask your supervisor for another assignment or at least some time to do some studying. Quite frankly, you don't know enough to even ask reasonable questions. There are literally millions of instruments that you can connect to an Ethernet network.

[crossrulz]

You can always make a string indicator and change the format to be hex.

Most instruments use an ASCII format for sending and recieving commands/data.  The fact you are asking for hex values tells me that you are most likely dealing with an internallly developed device.

As has been said, you have to know the protocol of whatever you are talking to.  It would be like if I went up to somebody in Russia and started giving them orders in Portugese.  They would just look at me funny and ignore me.  But if I speak in Russian, and they are more than happy to give me the information I asked.

[kdm7]

First of all can you please explain the concept of sending/receiving data and protocols and how actually the communication happens? 

I think an SB-rio is used (or something else). Could'nt find required information from the data sheet of sb-rio.

The thing is, there are various systems located at different places. This VI (energy monitor) monitors the different parameters (acquired from these systems) and displays the results (It is an internet enabled monitoring system). 

My question is,

There is a write buffer which contains some hex values (which I assume are commands to read required parameters). How do you configure these hex values?

How do you find out that these are the commands that should be written to read the required data?

Please help! 

[crossrulz]

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@kdm7 wrote:

First of all can you please explain the concept of sending/receiving data and protocols and how actually the communication happens? 

I think an SB-rio is used (or something else). Could'nt find required information from the data sheet of sb-rio.

The thing is, there are various systems located at different places. This VI (energy monitor) monitors the different parameters (acquired from these systems) and displays the results (It is an internet enabled monitoring system). 

My question is,

There is a write buffer which contains some hex values (which I assume are commands to read required parameters). How do you configure these hex values?

How do you find out that these are the commands that should be written to read the required data?

Please help! 

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sbRIO?  Yep, it is an internal protocol that somebody at your company made up.  GO TALK TO THEM!

You just write whatever you want to send to the VISA Write.  VISA knows which communication bus to use based on the session you gave it.  When dealing with a sbRIO, it is most likely using an Ethernet connection, so it will use a TCP/IP protocol to send the data.  But you don't care about that.  All you need to know is that you write the data to the VISA Write and it will automagically make it to your device.