PLCs vs. Industrial PCs

You should search the web first. "Pls very urgent help me........." NO!

anything with industrial in its name will be three times the price

<sigh>

The short answer is obvious if you know even the simplest of basics regarding a PLC and a PC, the more detailed answer (differences, features, etc) is easily found (easier than finding CR4 in fact).

Please perform a search of the internet for PLC and Industrial PC (also try Wikipedia) for your answer. If this is homework then I expect 10% of your marks for my assistance (or a standard consultancy fee for my time).

Engineering is about "considered", not "urgent".

PLC is call "Programmable Logic Circuit" and Industrial PC is almost the same as the PLC system but the hardware is different from PLC. Both system having the same function and both of these system can re-programmed the logic circuit. Both system are used in industrial for the control of machinery and automation system.

The difference between both system, in terms of programming the circuit are as follows:

1) PLC is more easy and friendly in programming the logic circuit where Industrial PC, you need to have more experience to do the programming.

2) PLC can used ladder diagram, block diagram and function block for programming and Industrial PC used Block Diagram. Both programming step are different from each other.

3) For Industrial PC, some of the system are pre programmed and you can't do any programming to it.

Please correct me if I am wrong as I haven't touch these programming so long time.

PLC:

• Pluses
• High temperature operation, no fans
• Vibration resistant
• No rotating media (no Hard Disk Drive)
• I/O can be on-board or remote
• No GUI drivers to consume processing power
• Deterministic operation
• No Computer Science (CS) degree needed for troubleshooting and maintenance (ladder programming matches what most electricians are trained on)
• Minuses
• No GUI unless connected to one elsewhere (typically)
• Limited memory for storing data or archiving, must be networked to a PC somewhere else
• Limited in non-linear processing capabilities, floating point math etc. (capable, but limited).

Industrial PCs

• Pluses
• Higher computing functionality
• GUI capability is inherent
• C++ or VB programming for nerd types (job security for them)
• Capable of local data storage and archiving without networking.
• Minuses
• Must be protected from extremes of temperature and vibration
• Higher temp operation adds significant cost, adds fans
• Non-rotating media (RAM disks) add significant cost
• All I/O is remote
• Deterministic capability adds significant cost
• Only the CS nerds can program and troubleshoot (risk of continuity for the owner)

In a nutshell, those who seriously consider industrial PCs are those who must have the PC there for some other reason anyway. Any other consideration is typically based on arrogance of a PC programmer who thinks "ladder programming is for idiots" but is not thinking about the poor guy who is in charge of making the system work at 3:00AM but has no idea how to spell C++. Either that or they are using false economy when assuming it is the same cost because they are not thinking about determinism and/or reliability, and thus buying the cheapest thing they can find.