PLC with MPC capabilities?

I'm not aware of any PLC with a standard MPC, but I understand
Emerson's DeltaV DCS has a standard MPC block. About a year ago there
was an article in "SA Instrumentation and Control" about Rockwell's
model based control in an Allen Bradley PLC, but that was about single
loop IMC and not MPC (that is if my memory serves, maybe you want to
check with them).

I'm sure the processing capabilities of modern PLC's would be more
than adequate for "simple" multivariable MPC, that is maybe without
for example real-time QP for constraint optimisation. If you want any
support and/or assistance in writing such a "simple" multivariable MPC
for a PLC, I'll be very keen to be involved in that exercise and I
don't think it'll take me more than week to do. I know you asked for
it to run in the PLC, but you might want to consider running MPC in a
PC with an OPC interface to the PLC. I do have a such a product, you
are more than welcome to download a demo version from www.randcontrols.co.za
(the demo version's OPC interface is disabled, so you can't control a
real plant with it though, for that you'll have to buy a license from
me).

Dependent on your requirements, another solution would be to do a
multivariable IMC, and that would be really easy in a "small" self-
contained PLC. This would not be as good as MPC, but it could be a
good solution (better than PID in any case) if all you want to do is
for the controller to compensate for multivariable process
interactions and the ability to control long dead time to lag ratio
processes.

Pieter Steenekamp

Check soft PLCs from Beckhoff (www.beckhoff.com) CoDeSys  
(www.3s-software.com) or K+W Software (www.kw-software.com).  The  
capabilities are almost limitless.

They can handle this with aplomb.  The advantage it is the Asset  
Management and other such applications programmed and integrated for total  
plant management.

If you are looking for hardware based PLC, look at TSX Quantum or TSX  
Premium PCX (for process control processors) from Modicon / Schneider  
Electric (www.telemecanique.com).  This hardware is targetted at mini-DCS  
applications since > 20 years ago.

thanks.




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thanks for your recommendations