Z
Zan Von Flue
> 1) You can easily find softPLC software that can be programmed in ladder. 2) There are also industrial PC's. you can find them with or without keyboard, with touchscreens or with only a few function keys so operators can't use them to install other application. 3) If you use a PLC and SCADA software then PC control with remote IO is cheaper. For small applications the PLC will be cheaper. I can think of some applications where a PLC would be better or safer, but in 80% of all applications you can change PLC by PC control. 4) If you use a good quality (industrial) PC, a flash harddisk and a Real time operating system a PC can be as reliable as a PLC. 5) Keep a PC control dedicated, once you have installed all software and hardware correctly you will never have problems with a PC
<--stop for point 1 and 2, your correct. However for 3, Scada information grows taking either softPLC time (this is not wanted) or the scada runs slower, so seperate the Scada and plc. This is not the idea. Also, small applications are better with a HardPLC, and I feel Large applications also. The expandiblity of a PLC is far greater then a PC. Plus you don't have to worry about the driver for the end device. Alone the video card in a PC now. If this dies (ok it happens) this card has to be replaced with a equivalent card and, who wrote the driver and DLL's? which is point 5- at least with us, a control system is yearly worked on. Other's can't leave things alone.
later
zan
<--stop for point 1 and 2, your correct. However for 3, Scada information grows taking either softPLC time (this is not wanted) or the scada runs slower, so seperate the Scada and plc. This is not the idea. Also, small applications are better with a HardPLC, and I feel Large applications also. The expandiblity of a PLC is far greater then a PC. Plus you don't have to worry about the driver for the end device. Alone the video card in a PC now. If this dies (ok it happens) this card has to be replaced with a equivalent card and, who wrote the driver and DLL's? which is point 5- at least with us, a control system is yearly worked on. Other's can't leave things alone.
later
zan