Modbus network access via GSM

[Jere]

Our Modbus network consist of M91 controllers acting as slaves and of one Vision 120 controller acting as master. For each Modbus node (M91 or V120) there is Unitronics RS232/RS485 converter.

If I connect my computer to the converters RJ11 port with communication cable, I am able to download a program to any of the controllers connected to the Modbus network just by defining the id number of the node. I'm also able to view any of the controllers in online mode through a single converter.

Now I would like to be able to similarly access the network from my office. I'm hoping to establish a GSM link between office and a single RS232/RS485 converter connected to the Modbus network. So my aim is to be able download a new program to every controller in the network via single RS232/RS485 converter using GSM link from my office.

Can this be done and how?

[Emil]

Hi Jere,

Modem cannot be connected to converter. It needs to be connected to controller, which will initialise it.

Maybe you can use some modem/rauter, like Sierra Wireless Raven EX, for example, and then serial to Ethernet converter.

We have no experience with such network.