thread277-4196 / Integrating PLC and SCADA

[MathiasV]

I'm responding to the above archived thread:
"shyam" wants to get rid of the problems associated to the interation of SCADA and PLC software platforms, and is looking for an integrated solution.

Take a look at our website at

http://www.biconsulting.com/new/en/Directit.asp

Direct iT is the SCADA component of a Process Control System Suite called Plant iT, which provides a Component-Based library in the PLC that interfaces directly with the SCADA platform. Since hardware and software components are already integrated, you can focus directly on the actual application software. This means, for instance, that you will be able to control your process manually in record time, investing only 50% of time required in classical non-integrated SCADA/PLC solutions.

Should you need any further information, please feel free to contact me

Mathias Vermehren

 

[FrancisL]

Hi Mathias
A very commercial comment that.
Anyway, I very much doubt that it is really true, sorry. Can you prove it?
Francis

 

[MathiasV]

Francis,

The best way to compare classical SCADA/PLC solutions with Integrated Process Control Systems is by breaking down and comparing the functionalities. We have made a case study based on experience values from the field, and we came up with the following figures. The percentages are based on total functionality provided for a given custom solution.

Basic functionality provided out of the box:
SCADA/PLC: 10%
SCADA/PLC + Batch Engine: 25%
Integrated Standard PCS: 50%

Just to name one example: if you buy a SCADA system and want to manually control the system, you will have to accomplish the following tasks:
- design and program your Valve&Motor controls in the PLC.
- design and program your V&M messages.
- design and program the corresponding Faceplates on the SCADA.
- design and program the communication handshaking between PLC and SCADA.
- design your SCADA screens.

In a Integrated Standard PCS, you will only need to:
- parameterize your Valves & Motors.
- Messages come standard, out of the box, no programming required.
- Faceplates come standard, out of the box, no programming required.
- Communcations come standard, out of the box. Only need to be configured.
- design your SCADA screens (standard ActiveX's are provided to interface with the V&M).

As you can see, it is not difficult to see that you will be able to gain manual control over your plant in much lesser time. This is due to the fact that most of functionaities come standard.

I'll be happy to provide you with more information as you require.

Regards,
Mathias.

 

[FrancisL]

Mathias
I well understand the principle. No doubt Emerson et al make similar claims. Your product is not unique in this respect.
However, 10 years ago I was auto generating PLC code for manual control and the associated Tag database for a SCADA from a master database.
It was not so much a product as a programming technique.

It is not the time to program the systems that is the problem in my opinion, it is the time working the out detailed requirements and hence what needs to be programmed. Those things like Valves and Motors by the way are easy, it is the operational sequences, complex control loops etc that take the most time.
But even with, say, a motor, sometimes (often) you need to design the logic, as there is not one standard that covers all the typesof motor and types of user. So with your system, can I change the valve and motors? Design new templates if you like.

Regarding "Communications come standard," I can see that for linking SCADA to standard 'objects'. But what about PLC-PLC comm’s? Often these need to be fast and need to be designed properly. An example from another system of how effective 'out of the box' comm’s can be is pump running for 20 seconds whilst it waits for an interlock signal (that should have stopped it fast) to be passed up to a PC, into some PC based logic and back down.

Then there is all the process specific and sequential logic, which cannot be canned. Where does it go in your system?

Francis

 

[MathiasV]

Francis,

The system is class-based, which means that each standard module is a class that has its component on the Scada level and its matchin pair on the PLC level. Valve and Motor classes can be parameterized to different types, such as one or two feedbacks, positive or negated logic of feedback signals, etc. Also each Device can be configured individually with different feedback supervision times. And there are lot of other parameters such as delay-on, delay-off, maintenance counters, etc.

There is a module for double-seat valves as well, same as Danfoss VLT's.

There are also modules for sequencers, which are recipe driven, with parameters. It also comes with a standard Faceplate on the SCADA.

Finally, you could develop your own User-Defined classes. So there is enough flexibility on that end.

There is also a PLC-PLC communication module. In any crosscoupling there is an inherent delay. In practical terms, the delay is about 1-2s one way. Depending on the nature of process, this might be ok or not. In the Food & Beverage as well as Chemical and Pharmaceuticals that we have worked with, this never has been an issue so far.

You brought up DeltaV as an example. Plant iT is a sort of Hybrid-DCS, similar to DeltaV, but with the difference it works with two mayor PLC manufacturers: Siemens and Rockwell. It is also much less expensive. Have you had experience with DeltaV?

By the way, is this Lovering?

Regards,

Mathias.

 

[FrancisL]

Mathias. Yes it is me!

I don’t think I actually mentioned DeltaV, I said “Emerson et al” . But yes I have DeltaV experience, quite a lot. The 'factor X' software that I produce has been used for the design of several DeltaV system, plus I have worked on projects where it has not. I could of course produce one of those comparisons between projects with and without 'factor X', and these would show massive cost savings, projects completed with 'factor X', in a third of the time etc.
But with all such comparisons there are huge statistical problems.
The sample size. Basically it is usually 1. Not even 2.
Nobody ever does the same project twice, at the same time, and with comparable management. So comparisons are mostly meaningless.
Yes, project A may have been faster or cheaper or whatever. But there will be so many other variables that it is not reasonable to pick out 'factor X' as the dominant cause.

About “sequencers, which are recipe driven”
With ingenuity I agree that sequencers can be very good. But, what about support for SFC’s, which are much more flexible. In fact all the IEC1131/3 languages (which after all Siemens and Rockwell support)

Next, supporting Siemens and Rockwell. Question. Once you have generated your PLC code, and you want to change it, (perhaps Have to in the middle of the night) what do you then have to do with your system?

PS
Does anyone want us to continue this off the Forum? If so please say.

 

[MathiasV]

Francis,

There is no PLC code "generation" in Plant iT.
Does 'factor x' provide this?

The problem I see with code generators is precisely what you pointed out at the end. Code generators are good only during the mass-engineering phase. Once you go online, it is easier to work directly with your programming software.

Regards,
Mathias.

 

[FrancisL]

Mathias

But you said at the start that you do not need to "- design and program your Valve&Motor controls in the PLC."
So how does the valve and motor logic get programmed?

ControlDraw incidentally does not generate PLC code, (potentially it could) but it can generate tag databases for PLC's and SCADA, or DCS's. In fact a big question is whether Plant IT is open so that it could import these. Can it? And do you publish an API or file structures for that purpose?
Francis

 

[denison]

I have some experience using a line with a bunch of AB plc's and a bunch of siemens S7 plcs. And scada to communicate (whatever that is). I'm a lead electrician in a bearing manufacturing facility, and use S5, S7, Logix 5, Logix 500, and Logix 5000 to troubleshoot and some cases, some simple programming or changes. I know for a fact (though I don't know what to do about it) The siemens S7's and the PLC 5's I have on the same line networked together lose track of each other at times. At times, seem worse, sometimes don't have a problem for days. Never been able to see what sets it off, but I know it happens. I won't go into how I know unless you want specifics, But I've been working on machine tools and similiar things for 25 years, trust me its happening, and suppossedly with a skew rate of less than 25 mSecs. They don't belong together, as far as I'm concerned.

 

[MathiasV]

Francis,

When you buy the Standard PCS License, the package provides a library of Control Modules (i.e. valves, motors, comparators, PID's, etc.) and Industry-Specific Equipment Modules (e.g. Temperature Control, Flow Control, etc.) that have two components: 1) the function in the PLC; 2) the faceplates on the SCADA/PC plattform. What you need to program is the interface to the CM/EM, in other words, your phase logic and recipes.