Controller Recomendations

Hi Folks,
We have a client with an application that will potentially have analogue values changing at micro-seconds rates. They are wanting to know what the dv/dt of these signals are, at all times, even though, if we end up selecting a PLC, we would not be able to act on these signals faster than the PLC's scan time.

What I was wanting to ask the forum, is some recomendations on PLC's with fast scan/analogue sampling times, or even some micro-controllers that would potentially be capable of this task?

So far, I have quickly compared the Modicon M340 & Omron CJ2 ranges, & it does seem that the Omron range has faster rates, in both CPU & analogue conversion time.
I have heard that some of the Siemens processors are pretty fast, & am about to look at the Rockwell range also.

We have thought about a motion controller, but don't need any of the axis control features etc, but it still may be an option due to the superior features they can provide.

The basic specs are:
8x AI
20x DI
20x DO

Any suggestions, perhaps even on micros would be appreciated. (I have been trying to find the recent thread on micro's, but cannot remember it's title...)

Cheers

I don't think the PLC world is for you - for microsecond speed I think you need data acquisition hardware from companies like National Instruments or Measurement Computing. There you might get in the millions of samples per second.

I second that National Instruments makes a PAC much like contrologix but they also have high speed data acquisition modules that work with it.

Lab View is function block based and graphical and is very easy to program but indeed very powerful. There hardware supports mosdt major industrial networks and can work with most other manufacturers PLC's also.

You may find something of interest in this link

http://www.plctalk.com/qanda/showthread.php?t=55672

Kalle

robertkjonesjr said:

I don't think the PLC world is for you - for microsecond speed I think you need data acquisition hardware from companies like National Instruments or Measurement Computing. There you might get in the millions of samples per second.

Click to expand...

Ahh, NI!! That was the one I could not think of, I will look at them.

KalleOlsen said:

You may find something of interest in this link

http://www.plctalk.com/qanda/showthread.php?t=55672

Kalle

Click to expand...

Thanks Kalle, that was some interesting reading. This application is somewhat similar, in that we need to know the rate that the signal changes by, so that we can adjust a limit accordingly.

I just checked the Rockwell Specs, it is possible to set a STI to be 0.1mS, that is pretty fast, would it actually operate at that?