Modbus via GPRS and Local RS485 Bus

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Thread Starter

Falko Jahn

Hi @ all!

I have developed a photovoltaic charge controller. This charge controller should now learn to speak "modbus". So it can communicate with other devices (eg, with the monitoring modules for the individual battery cells). This communication works so far (RTU over RS485, charge controller is master or or a local PC is master and charge controller is slave).

Now we want to get the data of the charge controller and the connected slaves by PC via GPRS (And send configuration parameter) Thus it can work without any special sim card, the charge controller has to connect to the server (so far i know). How is it now possible from the PC to poll the charge controller? The Modbus master simulators (eg Modbus Poll) can only poll to a specific IP address, it does not opens open a socket, so the charge controller can connect to it. Is there any software that it can? Or is there a other way

I hope my description was understandable and sorry for my bad English.

greetings
Falko
 
> You can use for example Moxa w5340

Hello, we have already a build in gprs modem from simcom (sim908). The questions is how to make the firmware and the software on the pc side.

The Software "Active OPC Server" for the Moxa w5340 looks nice. i'm looking for something like this but it should be open and not for moxa products only...

Regards Falko
 
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Mumtaz A Ansari

Well the scope and application is not that clear?
Is it a single device or in dozens?
Does your on board modem support DynDNS?
You can use any commercially available IO server which will probably solve your 'direct IP connectivity' problem usually faced in GPRS.

You can use any commercially available IO server for 'dialing' your modem on GSM for data or establishing IP packet connection based on DynDNS

You can also explore kepserver or imperious IO server for more info.
 
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Lynn August Linse

The GPRS modem acts much like your home cable or DSL 'router'. So when it connects you don't use phone numbers and are NOT charged by time. The GPRS modem will get an IP address from the carrier (just as your home Cable/DSL modem gets an IP from your provider).

So if your controller tries to connect out (for example, serial traffic force an auto-connect TCP socket to open), then the remote server will think it is the temporary IP assigned to your GPRS device which is connecting.

Calling out the GPRS device can be difficult, expensive, or even impossible! It depends on who the cellular carrier is (& which country you are in). Some countries do not even support 'dynamic IP' - all cellular devices will have non-routable 10.x.x.x like IP.
 
Hello,

There is a many solutions for this.
You can use for example the embedded computer with GPRS modem like Moxa W325.
You can use Embedded computer with Linux (for example FriendlyArm) + USB modem.
You can use programmable GPRS Modem like AirLink.
Also you can use ethernet router with USB modem (like TP-LINK MR-3420 it gives you the possibility to use DynDNS ) + Modbus TCP to Modbus RTU converter.

Regards,
Andrzej.
www.modbus.pl
 
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Hi,

And if you want to get the customized software we can design as SCADA that communicates over TCP/IP to Modbus device(s).
If you have some specific requirement then we can design it for you.
Looking forward for your reply on this.

Regards
Love Diwan: +91-9810013576
 
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