my configuration

[mr_shadow]

Hi all; Everyone know my question i think but i must ask again:) Before now the machines i programmed has short cyclic times but i always used Hardware PLC , but now i'll make a long cycle dyeing machine automation program with softPLC (i afraid it is soft), and.the PC will work on bad(hot) condition. In the PC, SCADA and Soft PLC will run together and the machine will have only one Electrical cabinet and the Panel PC will be mounted on this cabinet. As you understand my necessary things are; 1. Low cost Panel PC (15'') 2. Low cost SCADA 3. Low cost Soft PLC 4. Low cost digital and analog I/O units(in the same panel, distance is 3-4 metres maximum). As i r esearched My configuration is: 1. Low cost Panel PC----->Benecom(Thailand) 2. Low cost SCADA-----> Winlog SCADA 3. Low cost Soft PLC------> ? 4. Low cost digital and analog I/O units(in the same panel, distance is 3-4 metres maximum)----> ? Does anyone can give me reference especially for the PANEL PC, because i need really water resistivity and MAX temperature 40-45 Celcius. It says NEMA STANDARD but i know IP 65. Is NEMA ok for my requirements? And also with WINLOG SCADA?Did any of you used before? and can tell me something about it's flexibility? Thanks a lot

[paulengr]

NEMA is an alternative to IP. They have their own numbers. NEMA 4 means that you can take a 3 cm water hose (fire hose) and aim it under pressure at any angle at the cabinet without getting water inside. NEMA 1 means indoor/dry only. NEMA 3 means outdoor (rain/snow resistant). NEMA 4X means corrosion resistant but there are two variations. One is fiberglass (cheap) and the other is stainless steel. As to a "soft PLC"...here you have a problem. If you run a windows-based system, you will be subject to the lousy stability characteristics of Windows and the fact that real time means whenever Bill Gates believes that he's gotten enough money to allow you to use your PC. All soft PLC systems that provide any sort of gaurantees of stability run on bare hardware or on a better operating system than Windows. For those reasons I wouldn't even bother trying to use a single PC for both PLC and HMI/SCADA functions. There are some PLC's that have web servers. For instance, softplc.com has one built in. That's about the closest that you can get to an integrated system. Alternatively, I believe companies like ezautomation and some others sell operator interfaces that have a low end PLC bundled into the operator interface. Just because the cycle/response times are "slow" doesn't mean you can walk totally away from PLC's. You are talking about the difference between discrete, batch, and process manufacturing. They are definitely different but still require the same levels of safety, reliability, and similar controls. Process equipment tends to have slower cycles but much more analog IO than discrete. Batch is more concerned with arrays of recipes and mixes both discrete and process needs.

[JesperMP]

Low cost + low cost + low cost + "and.the PC will work on bad(hot) condition" = catastrophe. Why dont you go for a low cost PLC + low cost OP. If there are any PC-specific features you need, why dont you attach to the PLC with ethernet and have a separate PC program in a (low-cost) standard PC do the PC specific stuff. Place the rugged PLC in the hot panel, and place the standard PC in an air-conditioned office or control room. I suggest Automation Direct. Their PLCs and panels are cheap, and their ethernet modules are dirt-cheap.