LabView Modbus RTU

[MarcosBelgo]

Hi, I am using Labview for the first time and i have to make a comunication aboult a PLC and a PC.The device comunication is a NOVUS, that is a gateway RS485/wireless with protocol Modbus RTU on RS485 and a network without cable IEEE 802.15.4. What do i need to do first to comunicate with PLC? I need a DSC RT module for this? Can I make this without these modules? Thank you.

[MarcosBelgo]

I am using Labview 2012 Sp1.

[chembo]

I used the LabVIEW Real-Time Module for Modbus TCP/IP, which is probably the same as the Modbus in the DSC.

Here is some info about the LabVIEW Modbus API. This was released for LabVIEW 2014, but the text includes also links to a free Modbus library, which is probably available also for labVIEW 2012.

[MarcosBelgo]

I have to use a USB to connect a PC that is a master of network Modbus RTU. I think that ModBus TCP/IP can´t be used. Is it correct?

[chembo]

Yes, you need an adapter USB to RS232 or USB to RS485. I mentioned TCP/IP just because I used it in this mode.

You could use the DSC or take a look at the LabVIEW Modbus API (link in my previous email)

[MarcosBelgo]

The device that will comunicate wiith PC is a Gateway RS485/wireless that reports with other Gateway RS485/wireless conected to PLC. The Gateway have a USB connection with a master ( PC ) and its interface RS485 to comunicate with a modbus network slave. 

[MarcosBelgo]

Sorry for my inexperience, this is the gatway:                                                                                                                                                                                                          http://www.novus.com.br/site/default.asp?TroncoID=621808&SecaoID=709251&SubsecaoID=0&Template=../cat...

And I think I dont need this adapter. Is itcorrect?

[MarcosBelgo]

The USB interface of AirGate-Modbus  can be connected to a PC functioning as master of the Modbus RTU network.

[chembo]

I looked at the link posted above and briefly at the device manual.

When you connect the PC to the USB port of the AirGate and install the driver, it works as USB to RS485 adapter. You will see a 'USB Serial Port COM...'. You can use this COM port in LabVIEW for Modbus RTU communication.

In USB-Master mode you can connect the PLC or any other Modbus slave directly to the RS485 port of the AirGate (no wireless communication) and use the PC as Modbus master.

The wireless option allows 2 or more gateways to communicate to each other, but for your application this should be transparent once you setup the network.

But before starting with Modbus, you probably need to take a look at some LabVIEW training and look at examples. Here is a good start: Unofficial Forum Rules and Guidelines, particularly the Looking For Free Training section at the bottom.

[MarcosBelgo]

Thank you Chambo.

I studied these manuals and now , I would like to know Which module I have to buy . DSC or Real -Time ? Which is more simple and easy to work?
I have to set an Modbus Server to begins to comunicate the PC with the gatway ? The architecture of my project is a PC connected to Airgate communicating with other Airgate connected to PLC . Is Possible ? How is the data acquisition of this architecture?