Modbus related hardware and software

[Sojo]

I use a fuel cell which has ModBus protocol and its output is RS485 and I have a weather station which is also uses ModBus protocol but its output is RS232. I want to gather all the data they have and transfer it to a laptop which has labview. In terms of hardware what do I need to connect fuel cell’s and weather station’s RS outputs to laptop? Is a simple serial to usb or serial to ethernet converter enough? Lastly, in terms of software which module should I have?

Thank you

[Albert.Geven]

the software is the same, you need an rs232 to rs485 converter for the special module. It is only a hardware difference.

[Sojo]

Albert thanks for the reply.

I think my question is not clear, sorry for that.

1- What I want to know is "How can I connect fuel cell to my laptop and read the values in LABVIEW which fuel cell is already measuring so I don't need to buy extra sensors?" ,

I contacted fuel cell's manufacturer, they say it uses Modbus and has a RS485 output and I have commands.

2-  Because laptop does not have serial connection I need to buy an usb to serial or PCMCIA to serial converter. Can a simple converter do this work or should I have to buy this; https://www.ni.com/en-us/support/model.usb-232-2.html

3- And which one will be more reliable? Converting Rs485 to Rs232 or converting Rs232 to Rs485?

[Sammy Z]

Hi Sojo,

You are almost on the right track.

I recommend using the following modules:

https://www.ni.com/en-us/shop/model/usb-232.html

https://www.ni.com/en-us/shop/model/usb-485.html

As for software, please look at the following links:

https://www.ni.com/en/support/downloads/tools-network/download.modbus-master.html

https://forums.ni.com/t5/Reference-Design-Content/LabVIEW-Modbus-API/ta-p/3524019 

Regards,

Sammy Z.

[Albert.Geven]

Hi

If you are already reading data in LabVIEW from one module, you probably have already an interface.

RS485 is in fact a bus interface so maybe you can connect both instruments.