cstoica

I'm not saying that there are no PLC that are capable of doing some of the functions that I've mentioned in my thread (a good example is Modicon with Concept), but must of them are limited in this regard, and I'm talking about big players in the field (Allen Bradley, Mitsubishi). DFBs are still a dream for most of the PLCs... - CoS

In my opinion, a traditional PLC is a PLC that uses the '90 technologies (hardware and software). I would include in my list SLC with RSLogix500 software (without tag-based programming capability), Mitsubishi PLC with GX Developer 8.12 (an extremely limited DOS software running under a Windows OS and also I found it to be difficult to use for special IO configuration), and there might be some other PLCs, but I didn't use them so I cannot put on my list. There are also some advanced PLC, like ControlLogix with RSLogix5000, and top of the list Modicon with Concept 2.5. The major limitation that I see on a PLC (without an OPC server or some other interfaces) is that you cannot have some basic features, like: data logging, data storing, web page, retentive data, partial download, reusable code (excluding Concept), OOP (excluding Concept), and so on. - CoS

I've used a couple of PC Based Control systems with Beckhoff PC (Win2000) and TwinCAT. The first one was comissioned in 2002 and still working fine. I didn't see anyone playing games on the PC, but this might be because there in no keyboard or mouse, we just have a touch screen with a VB6 app running as a front end. I think the future is PC Based Control and only when you work with traditional PLC and soft PLC you can see the difference. I'm working now on a project with RSLogix5000, and there is a big difference, believe me... There are also other software that runs under Linux or QNX (like CoDeSys) so there is hope for those that are affraid of Bill Gates. -CoS