The thing that programmable controllers don’t typically do well is manage data. This is primarily because the memory is organized to serve the control programming environment and not designed for data applications. Separate memory must be allocated and the transactions necessary to interact with memory must be coded. This means a lot of overhead and limitations.
Communicating data to other applications outside the control system involves a variety of issues, the most significant of which is the fact that the PLC has execute commands to send, receive or store information. Then there are the issues of network topology for data from outside the control system, device drivers for the various types and brands of hardware, unique instruction sets for the transactions between the PLC and programs from Microsoft and others. A fairly complicated mess.
As more processes require data to be reported for quality and traceability, the demand for industrial computer is overwhelming. I don’t know what the dollar value is for the indusrial computer market, if any readers have information, please feel free to email. I know that is has to be in excess of a billion dollars. Whatever it is, it is a significant number. Probably equal to the variable frequency drives market.
Is this just another trend? A technology segment? or something else? I would vote the latter. This is the beginning of a major shift in how control gets done.
Fundamentally, what drives this trend beyond the need for data is the low cost of hardware. Consumer grade computing hardware is getting cheaper as economies of scale continue to drive computer costs lower. The $1000. laptop is a thing of the past. In fact, your $100. cell phone has more computing power than most control systems. Ethernet hardware is so cost effective that most industrial networking is going to end up there, like it or not.
So how do we bridge the gap?
The folks at ACS Motion Control and Advantech industrial computers came up with a unique solution. ACS has a “soft motion” engine that captures their almost 40 years of experience in motion control and makes it available on an industrial computing platform. The software includes an IEC 61131 ladder logic engine as well, so all the control needs are available in one environment.
What makes this arrangement so interesting is that the software is designed for implementation on a dual core PC. The ACS software takes over one of the cores and makes it a real time host for the machine control application. Then it takes over one of the Ethernet ports and makes it into an EtherCat port allowing interface with any EtherCat servo amplifier or other EtherCat device. No discrete wiring.
The Windows core is still available to run Excel or Access and store volumes of data on hard disc or static memory. The other Ethernet ports in the system are available to do communications with external devices without putting any major load on the machine control application because the transactions are done inside the architecture of the PC.
These systems come with the software fully loaded and burned in so they are ready to run out of the box with no commissioning required. A great time saver, a great way to conserve panel space and cost.