# PLC via Internet

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#### Toni Kaesbeck

All: I need to connect a PLC (which has a RS232 serial port) via Internet to a PC. The PLC is in a remote unmanned station with the only possibility to connect via a wireless phone modem to a Internet Service provider. I have found converters from the serial link into TCP/IP, but how can I dial up and automatically reconnect to an ISP, if there is no support on that PLC? Thanks for all replies! Toni Kaesbeck

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#### David Wooden Omron

Please send some more information, such as what brand and model PLC, what kind of communication you wish to initiate, what protocols are to be used, and any other relevant information you can think of. My first thought is that you may need to install a PC or other Internet enabled device at the remote location to handle initiation and protocol conversion, or possibly upgrade the PLC to a more recent unit that could be capable of those things. David Wooden Automation and Enterprise Solutions Omron Electronics LLC 1300 Basswood Road Suite 200 Schaumburg, IL 60173 (847) 884-7034 [email protected]

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#### Cory Schaeffer

Maybe I'm missing the point, but I don't see the need for the ISP. You will need a modem any way you look at it, so why not just dial up to the PLC directly from the PC. No is required at the PLC end and most PLC's have some form of dial up connection. Hope this helps... Cory Schaeffer Information Products Holland, MI

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I don't know your protocol, but if you can do Modbus, check out the Modbus Earth Station offered by NR&D at www.niobrara.com. It's an interesting idea for satellite connectivity via internet.

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#### Toni Kaesbeck

Thanks for all the replies. Some more info: - The PLC is "a proprietary hardware" (as is the SCADA), not an off the shelf brand and I have RS232 and 485 on it - I was trying to see, if I can do without a PC just adding a "little Internet box" - The PLC's are in a remote location (several hundreds of miles) with no phone cable and I need to use wireless dial-up to an ISP - It needs to be permanent on and automatically reconnect in case of connection failure "I have never seen a stand alone PLC with Internet capability but hey, I'm still too young to have seen it all ... " >>>> I guess we will be soon old enough to see one, even if it's not mine ;-) Thanks Toni Kaesbeck

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#### artb-bcs/swt

You should look at Genesis - GraphWorx with the webhmi server. I think it will solve your problem. www.iconics.com Regards, Art Bourdeau Web: www.bcsco.com Phone: 518-765-3667 Fax: 518-765-4033 Mobil: 518-573-4745

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#### Steven Landau

This works fine inside of a facility, but I have not been able to find a way to economically have a 24/7 dial-up connection provided by my ISP, which I can get the PLC to re-connect if it goes down. Anybody done this?? Steve Landau VP Controls & Automation SPEC 92 Montvale Ave Stoneham MA 02180 Office: 781-438-3337 Fax: 603-843-5097 Cell: 617-908-9232 e-mail: [email protected] e-mail to pager: [email protected] (short messages only) ----"THE ENGINEERS WHO BUILD"----

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#### Curt Wuollet

A pair of net connected Linux boxes, one on each end and a few dozen lines of C. These can be old 486's. Support is built in for automatic reconnection. One end should have a static IP address. We've been doing this sort of thing since the net belonged to DARPA. Total cost should be less than half of any of the proprietary solutions. Any UNIX systems programmer can write this for you, check with any university. No big deal. Regards cww

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#### Mark Meng

Another similiar product from B&R (www.br-automation.com), a PLC with Web-Server in-built. The PLC is actually a small PC-Based system with RTOS kernal, but the interface to user is a standard PLC programming environment. It is a rather new product from this company, you can contact their local representative for details. Mark

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#### Alex Pavloff

Get a static IP dialup from an ISP. Get an cheap PC from somewhere. Set it up with Linux. Use the diald daemon to keep a connection permanently up. Use the built-in ipchains utility to foward the relevant HTTP ports to the PLC. The PC becomes a transparent link between the PLC and you, with the added bonus of large amounts of configurable security (accessing the PLC data only after being authenticated via private/public key encryption, for one).

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