Web Browser to PLC

[lrob]

I have ocassionally seen reference to user web browsers to monitor PLC information. This also translates to web browsers used as HMI. Do I have a misunderstanding of this, if not what is the basic concept on this and where can I learn more on this subject?

 

[nornrich]

Most of the companies that provide HMI software will have modules that allow connectivity through the internet. In the past the factory automation projects I have been involved in have used Wonderware for HMI and remote access and monitor of equipment. You can find information about them from their website at

http://www.wonderware.com

Richard Nornhold, PE
nornrich@redrose.net

 

[GerH]

You are correct e.g.

Siemens have a comms processor for S7-300 and S7-400 that has a built-in web server to which you can download custom web pages made up with objects that they call "beans".
Basically it can be configured to show live process data on a web browser. CP343-IT, CP443-IT. Obviously not as configurable as a regular HMI but getting close.

Other manufacturer's like Schneider Quantum have "standard" web pages i.e. not user configurable that would be more useful as a maintenance tool e.g. to show status of PLC I/O card.

 

[lrob]

I found what I was looking for, I was referencing it incorrectly. I was looking for the OPC standard. From what I have gathered it is new standard format that all components data is converted to so that the data is capatible with more standard programs such as VB, C++ and other microsoft programs. So if you familiar with VB, then with a OPC server to a PLC, you can generate your own Scada package. Found one company that actually has a VB HMI package that uses this concept and packages for ease of use.

If any interest to others site is consolitech.com

 

[plcintegrator]

Here are two other suggestions for your plc web browser needs:

1. Intellution has a really cool web server module that basically takes any windows that you have created in Intellution and it will automatically convert them to web pages that can be viewed from anywhere. This is especially usefull for plant managers and other executives that would like to be able to monitor their process from anywhere. Intellution has drivers for all the major plc's. The url is

http://www.plcintegrator.com/intellution.htm

2. There is also a great tool that is less expensive than Intellution. This is called realflex. These guys make a product that runs in windows and also a product that runs in a very secure os called QNX. QNX is perfect for situations where you dont want to deal with the fun issues that windows can give you. i.e. unstable, not secure, etc...
Real Flex can display anything related to your process in a web page. Their demo is actually pretty cool when you install it the software connects to the internet and you can view a realtime camera video stream in downtown Houston, Texas that is pointed at an intersection. You can read information about this software at:

http://www.plcintegrator.com/realflex.htm

I am also an advocate of Wonderware. As mentioned above in nornrich's post, that is another alternative.

So there are a couple of different options that can be used. It's all about the size of your budget and the scope of what you need to accomplish.

Finally, my personal recommendation would be to use Intellution because they are the most diverse. I like the fact that VBA is built into IFIX. This means that basically anything that can be done with Visual Basic can be done with your process.

Hope this info helps.


For prefessional plc, hmi, scada, and electrical engineering visit PLC Automation, Inc. at

http://www.plcintegrator.com

 

[MrJP]

Let me ask a question ...

Do you guys feel there is a need for a simple software package that would enable you to configure a simple data display which could be access from ANY PC with a Web Browser?

This seems like it fills a void. Right now, if all you are looking for is to be able to access plant or process data from anywhere with your laptop or any PC over the internet, you have to purchase an expensive SCADA or HMI package plus add ons to enable the Web access. (and you typically still have to write some java or XML code)

What's your thoughts?

 

Mr JP,

I think you are right there is a need for a simple software package that would enable you to configure a simple data display which could be accessed from any PC with a web browser - your laptop, my laptop, anyone's desktop. Anywhere.

As you know, OPC is pretty much the standard way of getting the data between PLCs and SCADA/HMI. OPC servers are available for all the well known PLC brands, and most of the HMI/SCADA packages have OPC server built in to expose their tag databases. Assuming the data your are interested is available in one or more of those OPC servers, the OPC data can be read/written via the web. Our OPC client ActiveX toolkit OPCWare Client Developer includes several samples that you can refer to for OPC web interfaces. These samples demonstrate how you can use our product to accomplish what you described.

In simple terms, there are two ways to read/write OPC data over the web with OPCWare Client Developer. The first is through the web server, the second is through the web client.

To do this the first way, through the web server, you can use ASP pages, which run on the web server itself, so you don't need to have any OPC software installed on the web clients - you only need the OPCWare Client Developer OCX in one location - on the web server itself. This is a thin client configuration, and does not rely on DCOM to get the data to and from the web clients, just HTTP. You only need to worry about DCOM if the OPC server is not on the web server PC, and even then, you only need to worry about a single DCOM connection. If you could put the OPC server on the web server, this would totally eliminate DCOM. In any case, there is no DCOM between the web server and web client.

The second alternative is a rich client (or fat client), where you run the ActiveX at each web client and embed VBScript or JavaScript in the HTML on the client side. Assuming the OPC server is not located on the web client PC, this always relies on DCOM, and you also have the additional overhead of installing the ActiveX runtime on each client PC. You do get more functionality in this way, but at the expense of extra administration effort, and DCOM/firewall/security issues.

So the simplest configuration is definitely the ASP method, and I would recommend that.

You only need to install OPCWare Client Developer on the web server, no other software is required, apart from the OPC server(s) of course. You do not have to purchase an expensive SCADA or HMI package, plus you do not need to purchase add ons. You do need to have knowledge of ASP programming in order to configure the web server as an OPC client using OPCWare Client Developer, but most webmasters will have adequate ASP skills.

Sorry if this got a little long or sounds complicated, but it is simple really (I hope!).

Regards,
Neil Kingston
Data Layers

http://www.opcware.com

 

[lrob]

plcintegrator,

This is a little late,however I find it interesting that the products that you recommend to use are also listed on your company's line card. I was looking for a alternative to these exact products. For many of my applications these are over kill.

 

[OldPfart]

I definately do not agree that OPC is pretty much the standard for SCADA/PLC these days. With some packages it is but there are much better, faster ways. With Omron PLCs and Citect I always use Controller Link - better - faster - more reliable than OPC. Citect have specific drivers for just about everything.

Omron CX-Supervisor is inexpensive - you buy the development package once and then only run time packages - has all Omron protocols built in, of course, and OPC for everything else. You can use the inbuilt language or VB if you wish.

Citect does the same thing with their own language or VB - ActiveX etc etc. Is much more expensive but leaves most SCADA packages for dead.

Not real fussed with the SCADA packages mentioned here by the way. Do not like any of them. Love the way Citect handles graphics and trending - the best trending in the business. Comes with all drivers also - no need to buy a driver for each device.

WEB Client is also not a problem with Citect.

 

[lrob]

I am currently upgrading my older wonderware factorysuite 7.5 to newer 9.0. It has only taken me a week on and off. I use GE PLCs and I had to download the drivers from the Internet because the GE drivers on the disk were corrupt. I found this out because the support techs knew this. I have no reference to follow for proper installation. I had to unistall and reinstall several times because I loaded components in the wrong order, support techs informed me of this also. All this trouble to monitor some process information. I have not setup historical data collection yet,hopefully it will not prove to be as eventful. Food for thought on packages although tech support from wonderware is very good, I am having to call them for the wrong issues. If I did not already have Wonderware currently running I would have not used it, thus the reason for original inquire.

 

[industrialsoftwareNK]

Irob,

You experience is one of the problems that OPC was designed to eliminate. For the popular PLC brands, you can choose from several different OPC servers each from a different vendor. All are readily interchangeable. If one turns out to be unsuitable for one reason or another, you can easily pull it out and replace with another - practically a like for like change. OPC drivers are installed in a straighforward manner, and many of the components involved are standard core components, thus eliminating many of the issues with custom drivers.

OldPfart,

My post was a response was to Mr JP's post, where he specifically mentioned that he did not want to pay for expensive SCADA or HMI packages plus add ons to enable the Web access. I was never disputing that packages like Citect can do this job, but as you mentioned yourself, Citect is a much more expensive way to do things.

I think you should look into the merits of OPC, as it is the standard way to inter-exchange data between a range of data sources from different vendors, such as PLCs, DCS, SCADA, HMI, historians, and many, many others. It is not based on proprietary drivers that only work with one vendor's software. It does not limit you to the list of drivers that this one vendor provides. It may not be the fastest, or it may not be tops under whatever other technical headings you would like to assess it under, but whatever shortcomings it does have, these are not significant for the vast majority of applications. That is proven by the number of OPC installations worldwide. However, vendor-independent interoperability, ease and speed of development and licensing costs are often very relevant factors.

Using interchangeable OPC drivers, accessible via reusable components that allow you to access your PLC, DCS or HMI/SCADA data in a VB application, or just as easily in a web page, and at a low cost, is always a worthwhile alternative to expensive addons to SCADA packages like Citect.

 

[NasaEngineer]

All,

Iconics has really good OPC Suite of programs for OPC such as GraphWorx, DataWorX, TrendWorx, and ScriptWorx,etc. You will have to find the right OPC Server for your PLC. Each PLC Manufacturer will have there own OPC Server. I know that Allen Bradley provides their own OPC Server just like NI, Kepware provides GE OPC servers. As far view PLC information through a web browser, you set up some kind of web server where HMI screens and configuration files would be maintained at. If you have to connect to specific types of hardware where OPC Servers are not provided by the manufacturer, can still be created by writing your own OPC Server. Would recommend doing this in a .NET language like C# or VB.net.

 

[eli73]

Try this product. It is an OPC based HMI that is totally free. It works great. Has a Wonderware / Intellution look to it and is easy to configure.

http://www.rtpcorp.com/product_Netsuite.htm