PLC integration with SAP MII without OPC

[former_member614699]

Hello,

I have got a task where I am not finding any solution yet.

Requirement is to connect PLC's on the shop floor and SAP MII. Is it anyhow possible to connect PLC's which are not OPC compatible directly with SAP MII.

If the above scenario can be fulfilled then kindly advise me the process to integrate.

Thanks in advance.

Regards,

Rudrakshma

[Kevin_Hunter]

Hi Kaminee,

In my experience only the newest PLC's have OPC DA or OPC UA capabilities so you have 3 options.

1) Check to see if the PLC has modbus TCP capabilities (been around since 1979) and is supported by PCo.

2) Write your own source system for PCo using the SDK - not the most cost effective method if you have lots of different PLC protocols to deal with.

3) This is by far the most common approach - use a 3rd party tool to translate all the different protocols that your PLCs will be using into one standard (OPC DA or OPC UA). Examples are Telit DeviceWise, Matrikon and KepserverEX.

I agree with Mike that robust networks tend to be an issue and we recommend that you install PCo as close to the machines network as possible, it also has the capability of storing the data locally and retrying (a limited amount of data) when the network is available again. If you expect longer network outages and want to guarantee the data is not lost then I would recommend looking at Edge Services On Premise as this will store as much data as you want until the network is connected again and will then push the stored data to its destination.

Hope this helps.

Kevin

[agentry_src]

Hi Rudrakshma,

While it is possible, I would recommend against it. Why not install a historian of some sort to gather the data and store against your future needs. Generally you can get instantaneous data reads from PLCs or other kinds of measuring devices on machines, but those devices are often (especially on older equipment) just real time measurements. So then you would be using MII (and some sort of data store/database) to retain the measurement readings over time. Which is what historians will do much more efficiently (that's why they came into being!). PCo is also designed to work efficiently with historians and other data stores, so not sure why you want to avoid using either historians or PCo for this purpose.

Regards, Mike

[former_member614699]

Thanks for replying.

Furthermore, How many MII instances are required on the same? I meant plant wise one local MII server is enough?

[agentry_src]

Only one MII instance per plant if you go that route. You may only need a PCo instance with central MII retrieving data from it. That is more a business decision and often the local MII instance is desirable if applications are being used locally.

Cheers, Mike

[former_member614699]

Hello Mike,

Thanks for clarification.

Without Historian server, I think we can be able to integrate those PLC's if those are OPC compatible.

I have to make design architecture for Plant integration through SAP MII.

I have some basic queries:

There are total 6 plants which client want to integrate with SAP MII. There are lot of PLC's (Level-1) are there in each plant. Considering PLCs are Level-1 system we will not be able to fetch raw data from those m/cs. Moreover, all these systems are working in different network---so

My thoughts are to make interface:

1. I need to suggest the client to make those PLC's OPC compatible.

2. Plant wise there should be one central OPC server i.e all OPC compliant PLCs would be needed to aggregate and make it a One where all data for one plant get stored there.Once OPC server gets ready then MII will start their activity to install and configure PCo on that OPC server i.e Plantwise One PCo as well. By using OPC DA or HDA MII will get data thru PCo connector.

Please suggest me.

I am totally new regarding this plant integration.

Once the above points get clear to me, I will continue my further queries.

[agentry_src]

It sounds like a good approach. Many manufacturing plants do not have a very good or robust network, so having a local data aggregator like you mentioned is often (really often) the best approach. It is a bit more expensive to do it at each plant, but usually pays off in the near future by improving the data collection process. At times doing the collection directly to a central repository is problematic. It is also not unusual to have MII instances in the plant, but the key is good data.

Cheers, Mike

[former_member614699]

Hi Mike,

Thanks for your reply.

But if the PLC's are not OPC compatible then how can I gather data by installing PCo or historians.

Actually I am totally new on this scenario. If you throw some light in details on this, it would help me to design the architechure.

[agentry_src]

Non-OPC compatible PLCs? I have not been involved with interfacing to non-OPC compliant PLCs. I know that it has been done before, but don't want to steer you wrong on how to proceed. I would first check with the PCo documentation to see what is recommended there. You might also want to talk to AspenTech or OSISoft or one of the other Historian vendors. They will certainly have lots of experience and I am sure they would enjoy teaching you the benefits of buying their products for building such interfaces.

One other thing to consider is replacing the non-OPC compliant PLCs. In the long run, it is almost certainly more cost effective than trying to work around the non-OPC devices. This is especially true if you are only talking about a handful of devices (which, granted, may not be the case).

Cheers, Mike