If you are using LabVIEW 2014 and have the RT or DSC Module you can use the Modbus API and follow along with the Modbus Library.lvproj. If you do not have that you can try using the Modbus API
With the API you will need to create a master, read from X registers starting at register Y and close out the master when you are done. Exactly what registers you read from will be up to you or documented in the Laurel manual.
If you have any other questions can you explain what you are trying to do and what problems you are running into when you try to implemet that functionality?
Matt J | National Instruments | CLA