How many types of PLC's are there & name them?

Question

How many types of PLC's are there & name them?

Answer 1

Yes, like the other answer suggested, this is kind of a vague question.  There are many types of PLCs out there, even within a given brand.  It depends on the size of the application, your control system network architecture, etc.

As for names, some of the big ones are Allen-Bradley, Siemens and GE Fanuc.  Of course, within those brands a very wide range of PLC types.

Answer 2

Not clear what you mean by type. PLC's can be categorized in many ways.

MicroPLC's are tiny devices intended to replace a few relays. Compact PLC's are all-in-one units that are not expandable, but usually accept a few cards. Open chassis designs accept expansion chassis to take more cards. Modular units are built from components, can have very large numbers of I/O's.

I consider custom single board computer machine control boards to also be PLC's, not everyone agrees.

The DCS is at the top end; to me they are still PLC's, but most people don't agree. But, as you network these things together with Peer-to-peer capability, how do you distinguish?

There are many manufacturers, each with at least one proprietary programming language. Once you know one well, not too difficult to transition to others.Wiki lists the biggest manufacturers, if that's the question.

http://en.wikipedia.org/wiki/Programmabl...