HMI Integration with MII

[Former Member]

Hello MII Gurus, I have a expereince of Integrating MII with ERP but I am looking at automation systems to integrate with MII. I was checking data servers ( data conenctors) in MII and didn't find one connector which can conenct to MII, I know some knowledge about PCo do we need any middleware to connect to HMI's on shop floor which are capturing information from PLC's.

Thanks,

Kew

[Former Member]

Hi Kew,

I have personally had great success connecting PLC's to MII by using PCo and an OPC Server.

PCo can easily connect to an OPC Server such as Kepware KEPServerEX, or a HMI such as Wonderware InTouch, and it is very flexible in how it can pass the data to MII.

If a site has a PLC, then it should also have a HMI or OPC Server to get data out of it. And if the particular piece of software they use on your site is OPC compatible (most are), then you should have no troubles connecting to it via PCo and extracting the data to MII.

let me know if you have any questions

[jcgood25]

Perhaps a bit easier to provide direction if you listed some names of the HMI's you encountered on the shop floor.

From a PCo standpoint, unless there is a native connection available shown in this list (http://help.sap.com/saphelp_pco22/helpdata/en/32/ecfef7a0f0423f81da24d31c3221ed/frameset.htm) you will probably need to leverage either OPC-DA or OPC-HDA, depending upon the HMI's OPC Server type.  Most shop floor vendors have an OPC server that PCo can connect to as a client and serve up this information into MII through alerts or as a query source.

[Former Member]

Hi, Thanks,I have gone through the link which talks about Historians, I am bit confused here when i talk about Human machine interface ( HMI's) which are talking to PLC's on shopfloor, is there a way to connect directly from MII.

Thanks,

Kew

[jcgood25]

There are numerous HMI or Operator Interface manufacurers and model numbers with different abilities to communicate with PLC's and Ethernet.  Many HMIs use a serial cable or proprietary protocol connection to communicate with PLCs (e.g. Modbus, Modbus+, Data Highway, Profibus, DeviceNet, etc.), but this is hardwired and in most cases there is a physical limitation on communication wire length, so you'll often find that an HMI is just an electronic button board with touchscreen in close proximity to the PLC for stopping/starting equipment, changing setpoint values, displaying valve positions, etc.

By going with a SCADA system, or process Historian you will more likely end up with an Ethernet capable setup that bridges multiple PLCs, which exposes you to more tags and adds a valuable level of meta-data like tag names, tag grouping, tag description, engineering min/max values, etc.  Accessing a process point by rack/slot/point typically yields only a number, whereas even an OPC Server (often provided by the same vendor as the PLC or HMI hardware) can provide tag meta data and access to multiple PLCs.

If you are still looking to connect to a physical PLC, consider the direct connect options, and if it's proprietary or a serial cable, consider that even if you could string a cord all the way from the PLC to the back of your NetWeaver server, it would not work, nor would it be scalable to multiple PLC connections.  If the PLC is ethernet capable, you still need something to speak the 'language' of the device, which is what the OPC Server, SCADA, or Historians do very well with their device drivers, I/O servers, etc.

Once again - the specific manufacturing vendor and model number make the biggest difference when determining connection options.  Terms like HMI, SCADA, PLC are way too vague to give any specific answer, and my attempts to describe things above may only add to your confusion.