i/o server 2009

[sf5959]

Hello, I am trying to use the I/O server in Labview 2009 to do Modbus communication and I do not understand how it works. Does anyone have information on this and/or examples that I could use?

Thank you very much!

-Jeremy

[jareds]

Jeremy,

I/O Servers allow you to communicate with various external sources of data, such as OPC servers or Modbus devices, through shared variables.  Basically, once you create your I/O Server for a Modbus device, you'll create bound shared variables for the Modbus data items.  Here are a couple of items on how to configure and use Modbus I/O Servers:

• Configure Modbus I/O Server Dialog Box
• Using Modbus I/O Servers (DSC Module or RT Module

I hope that helps you get started with them. 

[sf5959]

Hello Jared, Thank you for responding to my post. I have already read these links and they were not very helpful. For example, there is no explanation of whether or not I will have to pragmatically open or close the port I am using. I was able to create the communication server itself, but when I go to create specific variables for receiving data from specific addresses, I do not understand how to select the addresses I want. When I try to add a "range" of addresses to read, a list of separate variables is created. When I try to use them, nothing happens...

For the "Using Modbus I/O Servers (DSC Module or RT Module" page, there seems to be a link to view an example, but I am not able to open that link for some reason. If there is an example, is it possible for you to send it to me?

Thank you!

-Jeremy

[jareds]

Jeremy,

When using I/O Servers to communicate using Modbus, you don't need to handle the closing or opening of ports.  The server engine itself will handle that part of the communication.  A list of separate variables is created when you add a range, because each address represents a data entry which we will represent as a variable.  What type of device are you trying to connect to?  When you try to use the variables, are you just trying to read from the variables?

The Using Modbus I/O Servers page is a copy of the help file from LabVIEW.  The link should work when you find the page through the LabVIEW help.