A possible customer of ours want to upgrade the control system of their district heating plant from an old SattLine system and we have offered a solution based on ABB Freelance AC700F and ABB DigiVis. They want to control the plant from their central control room in another plant and there are two ways of connecting the two sites: a direct phone line (unused) and a public 2 Mbit/s SDSL internet connection.

Against our strongest recommendation, the customer tech rep is adamant that we use their spanking new 2 Mbit SDSL internet connection, telling us that we're out unless we come up with a solution based on the SDSL connection. He claims the IS/IT dept requires access to all traffic going in and out of their network, refusing to even listen to our arguments that IS/IT doesn't have anything to do with these systems or their internal communications. The problem is that AC700F uses some kind of IP Network Broadcast messages (or Multicast, even ABB can't tell which one), a protocol specifically designed not to route outside of it's own subnet. Our only idea is to use some kind of hardware VPN modem between the CPU and the router but so far, our supplier haven't been able to come up with a suitable product.

We have asked ABB to supply a better specifications of the protocol used but so far they haven't come up with anything useful, referring only to 800xA (which indeed can be routed).

Does anyone here know if you can route Freelance telegrams over a public internet connection at all?

 

OK, My initial question is why offer an AC800F to replace Sattline when the Sattline is basically an <b>AC800M</b> controller ? But of course it's your choice.

Digivis Communicates directly to the controllers and does not use OPC. Basically, without OPC, even if you could get the 800F to communicate with Digivis over the SDSL network, it would be totally unsupported. It is not a risk that I or anyone else should recommend you take.

You could use AC800F controllers with 800xA - known as "800xA for Freelance"

The standard ABB solution for your problem is "MultiSystem Integration" (MI). Basically, you install a small local 800xA system at the remote plants - and another 800xA system at the central control room. The systems are then linked over a Wide Area Network - in your case, the customers SDSL network. Multisystem Integration is designed to be robust even if networks have problems like limited bandwith, slow comms rate etc and is quite successful.

Note that although you have been told that 800xA "can use routing" this may not mean what quite you think it does. ABB's proprietary Redundant Network Routing Protocol (RNRP) is designed to increase the reliability of an ethernet network by routing packets over redundant networks. However, it will most like work quite correctly over your customers SDSL.

Also Note: You will need to verify with ABB that 800xA for Freelance is compatible with MI. If you choose to use AC800M instead then you wont have this problem.

Rob
www[.]lymac.co.nz

 

> OK, My initial question is why offer an AC800F to replace Sattline when the
> Sattline is basically an <b>AC800M</b> controller ? But of course it's your choice.

<b>AC700F</b>, not AC800F. And I was wrong, it's a SattCon 35 (not SattLine). The system is simply worn out (I/O-cards failing, CPU halting, memory errors, communication errors etc). From what I understand, 800F is a hybrid between Freelance and the 800-series while 700F is based on an older design from Hartmann & Braun (acquired by ABB in 1999).

> Digivis Communicates directly to the controllers and does not use OPC.
> Basically, without OPC, even if you could get the 800F to communicate with
> Digivis over the SDSL network, it would be totally unsupported. It is not a risk
> that I or anyone else should recommend you take.

That's exactly what we have been telling them and what they refuse to listen to. My guess is that they have invested in the SDSL connection without knowing what they need and now have to justify the investment to their boss (by referring us to some vague guidelines from the IS/IT dept).

> You could use AC800F controllers with 800xA - known as "800xA for Freelance"

---- snip----

> Also Note: You will need to verify with ABB that 800xA for Freelance is
> compatible with MI. If you choose to use AC800M instead then you wont have this problem.

Thank you for your help, unfortunately I just got word that we lost the deal as we could not meet the requirements.

 

Apologies, I should indeed have said 700F instead of 800F. Both are programmed with the same tool and are part of the same product line and included in 800xA for Freelance.