MathHead

OK thanks for the input. When you say "provide more details" that is part of the issue. I buy hardware and software which are supposed to work together, and if they don't, we get into a lot of networking and protocol issues which in order to resolve takes really a lot of time, and truthfully, I am a controls engineer with a lot of projects on my plate, and I don't have the time or even knowledge to troubleshoot arcane networking problems between different vendors. The other issue is that Beckhoff designs their systems and software, it seems, for computer science folks, not the type of controls engineer I am anyhow. I specify transmitters, valves, mass flow controllers, etc. , and then write PAC software to control it all. I like to use predefined function blocks and simple scripting, not write C++ modules to do what I want. It may be a difference in approach but that is where I am coming from. Automation Direct, for example, while it doesn't support a whole lot of function blocks and scripting language, is at least easy to use, and everything you need comes with, including free development software. That's my kind of product -- again, maybe a matter of personal bias and background. I have used Kepware OPC servers in the past, and they are very good, but again, not free, and might not solve the problem. If I can get Modbus working (again, on Beckhoff side, this is not straightforward at all) at least I know I can have reliable communication to my HMI and email server. I appreciate your input to my problem.

Thank you imankarmi. We are using a CX5020-0120 processor, and an Indusoft HMI running on Windows 8. The Indusoft HMI is a web server which gets tags from the Beckhoiff PLC via TCP, but what specific protocol I don't know. Indusoft points the finger to Beckhoff, and Beckhoff says that the problem is either with Indusoft, or our company LAN, and our IT folks say they understand only PC's, and don't know about industrial protocols. Does that sound familiar? That said, you are right on abut the Modbus server. I am setting up the software now, and when it is working I plan on getting the data to our Automation direct Productivity 3000 PLC, and redoing the HMI to connect to that PLC. We have another system using a Productivity 3000 with an InduSoft HMI, and we never have any connectivity issues. Thanks for your input, and if you have any further input now that  have provided the correct model number, I am very open to learn more. Thanks again for your reply to my post. John Wagner aka MathHead

I am using a Beckhoff windows based controller, with  TwinCAT modular I/O (EL series). I have several problems: 1) Our HMI frequently loses comm. with the PLC. Beckhoff seems to use their own special networking. 2) The PLC ladder language supported is very rudimentary. For example, I had to create my own function block just to do simple analog scaling. 3) Their documentation is pretty bad -- Web based and very hard to find specific information. I would like to replace the Beckhioff controller with a more standard industrial PLC (like Automation Direct Productivity -- I like the programming language and ease of use.) My question is -- how can I use the existing Twincat I/O with AD, for example Modbus TCP. Is there some sort of gateway available for this purpose?