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i have a panel multimeter that i use for my whole house that has RS485, Modbus RTU comunication.
I know what registers to read in order to get currents, voltages, power factor etc
How can i use this and get the data to a PC, i have an arduino but i don't know how to get this started
I've tried using a RS485->Ethernet converter and then tried to send comunicate with the device via TCP-IP but it's rather difficult (this method would be the best, netowk conectivity ensures i can have the data parsed at my server)
I have sucessfuly conected an RS232 device -> Ethernet convertor -> PC, but in this case the device (a PBX) sends the data clearly in ASCII and it i manage it easily with a small Python program that reads the data and then puts it in a mysql DB


How would you reccomand to connect and program sometging like this:
Meter with RS485, Modbus RTU -> RS485 to Ethernet convertor -> PC with python script getting all the data (it's gonna have to be a lot of HEX coding that i would need a getting started point :D )

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  • \$\begingroup\$ Your question reads as if you've already found a solution. What is the problem? \$\endgroup\$ – tyblu Dec 24 '10 at 20:03
  • \$\begingroup\$ I can't seem to be able to make this work? Is this supposed to work ? Am i doing anything wrong.. ? \$\endgroup\$ – s.mihai Dec 25 '10 at 7:19
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    \$\begingroup\$ I'm not sure why you'd go to the expense and overhead of Ethernet; RS485 and ModBus is trivial to work with with any small microcontroller and even simpler with a PC. There are ModBus libraries freely available if you want to just plug and play, and there are many companies that make inexpensive (under $20) RS232-to-RS485 converters; you just read and write to the normal serial port. \$\endgroup\$ – akohlsmith Dec 25 '10 at 21:25
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Take a look at MODPOLL. With this simple utility you can read registers from MODBUS TCP/RTU/ASCII slaves. When you make it work and read first registers, then you can analyze it's source code and use it from your PC. To use MODBUS from python, you can use this, or just parse console output result of MODPOLL. You choose.

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