Quantum equivalent to Siemens S7-300 or S7-400?

I have started a new thread for this discussion.

Previously I asked:
If you were migrating from quantum to siemens, would the equivalent siemens PLC be the S7-300 or S7-400?

I am thinking the S7-300 is more like the M340 and the S7-400 is on par with the Quantum?


To which OZEE replied:
You really ought to start a new thread for this instead of piggy-backing on an unrelated 2-year old thread.

We'd really need to know more about your application before anybody can make that kind of recommendation. Things like amount of distributed I/O, PID's, etc., will play a lot more into the decision than just the "physical architecture".

Honestly, unless you're into a really large system a -300 will most likely do everything you need and more.



And now V0n would like to supply more information:
My application is control of turbine-generators. Typically have 640 IO; 200 on main rack, two remote IO racks located within 100m of the main rack with 200 IO each, and another remote IO rack 500m-10km away on fibre with 40IO.

There are usually 5 PIDs, of which only two need a response time less than 100ms. I have one high speed counter for measuring period of 60Hz signal.

My application doesn't warrant redundant CPUs, and there are no spares around for hot-swapping, so if the difference between S7-300 and and s7-400 is redundant CPU and swapping IO without stopping the PLC or building the program, that isn't a reason for us to use S7-400 PLC.

Anyone who is familiar with the practical difference between S7-300 and S7-400 please chime in!

S7-300 Starts at M340 levels and goes way past as you move up. 319 is a beast. S7-400 is more similar to Quantum in footprint and can do hardwire redundancy.

Nick

ok thanks this is kind of what I suspected. The S7-319-3 is what we have been quoted as a replacement for the quantum, but the pricing is about halfway between M340 and Quantum.

We're not considering switching from quantum to m340 so if we are using a siemens PLC we want to stick with the same calibre product as quantum.

Von,
At my company we use both AB and Siemens for hydro control systems. Largely the need is dictated by the number of I/O's and the complexity of the hydro unit. In general, small hydro units are fine with either a compactlogix or an S7-300 PLC. I classify small hydro as up to 30 MW. Note that if you start getting above 20, you really need to look at the subsystems for complexity.

Also, are you integrating the digital governor into the unit controls? If so, you need to do some scan time calculations to make sure that you can meet IEEE 125 governor response times.

Thanks for the reply,

Are you using the S7-319 CPU or other?

Yes all units are less than 30MW, but we would only have 1 PLC CPU for a 30MW plant with 3 units.

The digital governor is usually integrated. If it is not, we probably wouldn't change PLC unless the PLC was really doing next to nothing.

IEEE 125 specifies speed deadtime 0.2s. The deadtime of 200ms for the machine to respond to a change in speed should be easily met by any PLC I've worked with if 1/4 of the 200ms is allocated to the PLC scan time for computing a new CV and the rest to detecting the change in speed and actuating hydraulics.
Does this agree with your experience?

I assume this would have to be an older Quanum, or you wouldn't want to replace it. If you are using the older 186 based quantums, then just about any currently available S7-300 has better processing power.
Also, the S7-315 seemed to have picked up a floating point co-processor a few years ago, so it is much faster on loops than the older generation of 300s. In fact, the latest 300s will leave any and all of the older (+10 years ago) S7-400s for dead.
One major advantage of the 400 though, is the ability to have more than 2 animated windows open at once. This helps in trouble shooting.
Finally, I would look at the IO first, and how to set this up. Will you be using Profibus or Profinet for your comms? One trick I have used in the past is to setup all IO on ET200M (Same as S7-300 IO), and then have the footprint for the CPU Rack big enough for either a 300 or 400. This rack contains only the CPU, power supply and master comms modules (Profibus, Ethernet and Profinet). If the 300 is too small, then it can be easily upgraded to a 400, with only a day needed to modify the code.

We're thinking ahead to future projects, not ripping out any quantums, so they are all the pentium 200 model.

We would be using ET200M for remote IO, and then whatever it speaks back to the S7-300 CPU. we've been all modbus in the past so whatever it speaks (profibus/net) I haven't ever seen it yet.

That is a very good idea though to leave space for the 400 CPU and have all remote IO.

In Unity I am able to open 7-10 animated windows, each showing a different task or animation table, before it tells me I have too many. Can the S7-300 really only show one task/subroutine/animation table at a time?

Why are you leaving Quantum?

Do not forget PREMIUM that is between M340 and Quantum. I would compare it to high end S7-300 or low end S7-400.

I know that Schneider has some new stuff going on where the entire backplane of their PLC is actually Ethernet and you can easilly expand.

Not leaving quantum for technical reasons. I don't know the exact motivation; some type of business reasoning I don't understand.

I haven't ever considered premium, I thought maybe it wasn't unity for programming but the website says it is.

thanks for your input

The S7-300 allows 2 animated windows.
The S7-400 allows a lot, I have never had so many animated windows open that it prevented me from opening more.

PREMIUM is good. We use it for powerplants. It is programmed in Unity and has redundancy and a lot ocf communication ways.

PREMIUM is good. We use it for powerplants. It is programmed in Unity and has redundancy and a lot of communication ways.

If you only have on PLC for 3 units than I would suggest using it as a control overlay. Only have it interface to the existing controls. We try to keep all of our unit controls as being able to operate stand alone. That way upper level failures do not affect your ability to put any single unit online.

unit PLCs would be nice, unfortunately not in the budget for the smaller plants

Do you have unitized governors and basic sequence controls, or is your one PLC all that is planned?

If your one PLC is it, than I would get the fastest PLC possible so you can attempt to meet IEEE 125 governor requirements. Profibus is fast enough for governor control, you just need to make sure that you don't overload it. I would suggest separating each unit and have 3 distinct and physically separate Profibus networks.

This link gives you an idea of the capabilities of the 400 processors http://www.automation.siemens.com/m...Images/s7-400_controller_leistungsklassen.jpg For your application I would pick a 417-4. This processor also gives you 3 onboard profibus networks.

If you are providing a 300 processor, here is a similar link: http://www.automation.siemens.com/m...hure_simatic-controller_en-34_performance.pdf

Here I would suggest the 319. I don't think that the 319 will be able to meet IEEE for 3 unit governors and it is questionable if the 417 will be able to do it.