Can we use satellite broadband for this app?

We are installing an SLC5\05 and some Wonderware SCADA PC's into a quarry in the middle east and require remote access from our offices in the UK.

Unfortunately there are no landlines in the vicinity as the nearest civilisation is 70 miles away. The ideal solution would appear to be satellite broadband as this would also bring WWW and Email facilities to the site, but I am worried about latency issues using a VPN to communicate with the PLC's.

Does anyone know whether RSLinx would be able to cope with the delays caused by latency or is there an alternative which would work?

Thanks

Steve

Satellite latency

Hi:

Six months ago I commisioned an aplication for a client with VPN communication using DSL/GPRS/Satellite. The ping time was the same for GPRS and Satellite around 800ms. For supervision tasks this shold be enough.

Bes Regards,

I use satellite based ISP from home and occasionally have to log in using remote desktop to troubleshoot a PLC.

I log into my work PC from home and then use it to connect to the PLC I need. It is very slow, but useable.

One quirk with remote desktop is that RSLinx and RSLogix must be left running on the desktop at work or I get a license error.

The latency here is more like 2-3 seconds. When first started, the connection can take several minutes to finish updating hte desktop, but once that is done, the latency issue is the only real problem. I just have to be very methodical when I type or use the mouse.

Yes, RSLinx can cope with the packet latency introduced by satellite IP connections. The performance will necessarily be greatly reduced compared to a local Ethernet network, but the connections are ordinary TCP/IP on Port 2222 and 44818.

Some configurations in RSLinx Classic that help reduce timeout errors are in the Communications -> Configure CIP Options menu. Set the retry timeout to 4 seconds or higher, and cut the number of Fast Messaging Connections to 2, the number of Slow Messaging Connections to 1.

For some excellent in-depth discussion of IP over cellular, which translates a great deal to satellite, have a look at this website: http://iatips.com/blog/

Yes, I've used RSLinx over a satellite shot. It felt slow but was functional. One customer was developing proof of a concept project that had similar slow links to a project in Alaska. He found that KepServer Ex worked better than RSLinx, although he may not have optimized settings properly. One specific feature that he liked about Kepware was the ability to enable/disable communication by writing to a local Kepware tag. The link was expensive so he'd have the HMI establish communication when the user opened a window. That introduces more delay, but saved money.