Modbus RTU connection to PC

General Discussion
1

Hello All,
I need some advice/guideline for a weather station project currently I am working on.
I have a weather station from Rainwise PVmet 200 that has a RS485 connector on its main board. The goal is to have the data from the weather station on a PC that is placed nearby. How can I achieve it?
I also purchased an RS485 to ethernet converter that might come handy but still, I am confused how to get the data from 5 sensors (i.e. wind speed, wind direction, solar irradiance and PV panel temperature) on PC?
If anyone can help or guide me through the process, I’ll be grateful.
The picture of the PVmet 200 main board is attached here;

PVmet%20200%20main%20board
PVmet%20200%20main%20board1080×944 149 KB

Kind Regards,
Mohsin

2

First, you would need the documentation from the maker that provides the details of its communication protocol. (Register addresses for each variable of interest.) Then with the Modbus module and the gateway serial module, you can make a Modbus serial connection. Or without the serial module if you go through the ethernet converter you purchased.

3

I agree with what Phil said. I typically prefer to use TCP over RS-485 from Ignition, but either method will work.

4

Hello,
Once the hardware connection is done from weather station to RS485 to Ethernet converter to the PC, what is next? How can I see the data of temperature, solar irradiance, wind speed and wind direction on PC?
The unit doesnot have any software with it.

Regards,
Mohsin

5

Start here for more about Modbus device connections.

Edit: You do have Ignition downloaded right? Any help here will mostly be in reference to connecting to the device using Ignition SCADA software. You can download a trial version here

6

This is the link to manual. Modbus registers start from page 11. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.fondriest.com/pdf/rainwise_pvmet-200_manual.pdf&ved=2ahUKEwiLz5j1xvnfAhUL3Y8KHV3XD20QFjAAegQIAxAB&usg=AOvVaw3zkImnbjh2I1ZdPAVdCQyP

A couple of quick observations:

  • Node id is 60 (many devices and software default to 1, so your 485 to TCP converter would need to be set with this ID.

  • Baud rate 9600, parity none, stop bits 1. The converter will need to be set with these settings.

  • To read ambient Temp you could try to read register 40072. This would be a holding register read. If that fails you should try analo input register 30072 (manual is not clear on command type) if that still fails some devices use weird offsets so try one register above and below, ie 40071 or 40073 / 30071 or 30073.

Good luck, hope you get it sorted!
Vds