difference between FPGA and PLC

Hi can anyone tell me the difference between PLC and FPGA,

Which one is better.
How about the performance, speed, Power, accuracy, security etc...

Thanks in advance.
Venkat

This two things are completely different .Fpgas are building blocks of electronic systems .PLC are systems . Is equivalent to asking what is the diffrence between a CAR and an engine .

Hi John,
Thanks for your reply. I wish to implement the PLC operation into FPGA example: controlling the machines etc.
If so why it is not used frequently
what are the issues to be considered during the conversion.

Thanks & Regards
venkat

It could be done .But for industrial purposes you don't need speed neither a massive parallel archirecture . A Microprocessor base machine is simpler .Also the users are techs .And what is required is a simple programming language like LADDER logic based. But fpgas can be used .The problem is that programming enviroments are complex .And designs need to be verified .So to me is an OVERKILL .But i've seen a couple of thesis of implementations. Now if an soft CPU is impelmented in the FPGA then it makes more sense .The cpu could be much easier to program with user programs and still there would losts of resources for implementing ports and timers etc.

Dear John,
I understand that you have said. Can you send me the thesis links that you
have gone through on these topics.
which type of low cost FPGA might be suitable for these type of experiments (including some DSP application),
I just wish to give solutions, to companies which were working on these issues (like board they required and interface that they needed etc).
what about SPARTAN 3E or 3A.... !

Thanks & Regards
Venkat

Hi Venkat,

As whats probably already covered; From what I gather a PLC is an embedded micro-controller (has processor) system whereas FPGA is a blank chip for circuit design.

But I wonder if you're getting at the same thing I've been wondering myself for a while. With FPGA technology and with Ladder-Logic representing Low-Level circuit design (relays) wouldn't it be more efficient to skip the whole processor system and just drop ladder-logic directly only the FPGA with high I/O count? If someone has more light to shed on this; I'd certainly find it most informative.

From where I sit; Ladder-Logic -> FPGA would be a big step forward for both FPGA design suites and PLC automation since FPGA by nature are designed to run parallel instead of sequential like a micro-controller.