Still, there are some alternative networking methods that come from treating this as a basic engineering problem. In the 1970s, Ladder Logic was supposed to turn electricians into programmers, and it did for the most part. However, we also learned that you can't turn a programmer into an engineer because programmers can give you the code you need, but you can't begin a project by programming blind. So, software and IT must support engineering because its bottom line is the process, understanding how it's supposed to run, breaking it into parts, and prioritizing those tasks to help it operate better.
For instance, six years ago I worked on a SCADA upgrade for the Whatcom County Water Dist. 7, which serves 2,500 to 3,000 customers, and covers just 10 square miles outside of Bellingham, Wash. This small water utility has nine main facilities including a 75-foot water tank, booster pump station, three or four reservoirs, some other pumps and many wells. The district's managers and operators wanted to reduce their manual controls, increase capacity and ensure more secure operations. So we began adding wireless networking and other components. However, this area is so hilly and has so many trees that wireless was a big challenge, and we had to use a combination of spread-spectrum ISM, spread-spectrum IP, broadband and DSL.
One simple but important signal we had to bring back to the district's 12-in. panel PC was just 2 bytes of data about the tank's level, so the booster station would know when to fill it. We put a wireless IP connection on the tank, dropped the signal to a SCADA station, and then sent it via a second wireless IP connection to the panel. We then accessed the booster station via another IP connection to transmit pumping instructions, and recently added a Phoenix Contact mGuard firewall to protect the whole network.
However, even though we put together a workable solution that can be used remotely, as we've refined it, I still wasn't able to make an iPad into a client that can reach the district's servers. It's very frustrating because there are many times when public utilities operators need data, but can't access it when they're outside the control room in the field.
As a result, I installed a $250 GE VersaMax micro PLC, and added its $130 option for an Ethernet slot and port, which can communicate via TCP/IP, 485 and 232, and use Modbus TCP and GE SRTP. This gave me an Ethernet-ready PLC for $380 that can network and control all of Water Dist. 7.
So my question is this: Who is the target for the traditional $3,000-5,000 lines of PLCs and PACs that still have serial ports and only offer Ethernet or wireless ports as an exception? The rest of the world is going to very inexpensive solutions such as iPads, disposable phones and network components linked by generic TCP/IP, WiFi, EtherNet/IP and Profinet.
I'm really looking towards this next generation of very small PLC-type processors with low-cost Ethernet adapters and free software from suppliers such as AutomationDirect, Turck and Hirschmann. I've also been on MySCADA.org, which sells digital interface screens for $10 and its HMI development screen and software for $300, but I still need to check if they can be used in each location where the user might go.
Sooner or later, iPads and other tablet PCs are going to be able to access these networks better, and read and control what we want. There is a lot of momentum for getting rid of problems such as not being able to see Flash programs on an iPad. Suppliers will figure out how to present information so it's universal, secure and capable in any device, and then we won't have to be programmers any longer.