RS-485 port Modbus I/O server sbRIO-9636

[rd.mcdt]

Hello,

I have a sbRIO-9636 which I am using to establish communication with an energy meter using Modbus I/O server. I am currently using Modbus Ethernet, but what I am looking for is to use the RS-485 serial port of the sbRIO-9636 and change Modbus Ethernet to Modbus Serial. I have never used the serial ports of the sbRIO so I have no idea if I need to configure it or something. Can the Modbus I/O server configuration link the serial port (in the range from COM1 to COM32) with the RS-485 of the sbRIO?

Please help!

[Timmar]

Assuming you are using libraries,

Change from ethernet to serial in your I/O server.

You will need to select the slave address corresponding to your target, Com port and settings.

you will also need to make sure that you have the serial drivers installed (they should auto install with the modbus library but it is worth a check).

[rd.mcdt]

Well, first thanks for the quick response, but I think I need a little more help. I already know how to change those settings. Let me try to explain a little more what I am looking for.

I am using the sbRIO-9636 as the master (right now using Modbus ethernet) I know that the sb-RIO has a RS-485 which I want to use so I can change from Modbus ethernet to Modbus serial. I don't know if it's possible (and if it is how) to link the serial port RS-485 of my sb-RIO (which is the master) with the Modbus I/O server Com port (after I change from Modbus ethernet to Modbus serial). Like setting the RS-485 of the sbRIO to be the COM1 so I can just select it at the Modbus I/O server configuration.

I hope this makes sense.

[JuDa]

Hi Criss_d

You can use your RS-485 port from your sbRIO-9636 as a Modbus Serial Master. There are several ways you can achieve this:

1. Using the LabVIEW Modbus API - This is the prefered option when your application needs a high level of control over the sequencing and timing of Modbus requests.

Getting Started With Modbus in LabVIEW

2. Modbus I/O Servers - You can use the I/O servers from LabVIEW DSC or the Real-Time Module. This is a high-level engine that will allow you to communicate over Modbus. 

How LabVIEW Uses I/O Servers

2. Modbus TCP and Modbus Serial

Choosing between Modbus I/O Servers and Modbus VIs (DSC Module or Real-Time Module)

Configure Modbus Slave I/O Server Dialog Box

LabVIEW also comes with a couple of examples on how to use the Modbus Library and the I/O Server. You can Find them on LabVIEW>>Help>>Find Examples>> Search Tab and look for Modbus.

Hope this helps. Any other questions feel free to post them.