Programming Mental Block

Ok I have a mental block and am in need of great big bag of inspiration.

Have an application on Siemens S7.

I have a Drive block with an associated instance.

This is to interface to an HMI.

The HMI is to use a common DB for all drives, populated by the PLC. This is mainly driven by the client not accepting scripting, this is how I would prefer to do it.

So from the HMI I will set a unique number for each device which will in turn populate the FC from the specific drive instance.

My mental block comes from need to start/ stop each drive from the common faceplate using the common HMI data block.

Just can't find the inspiration to reverse the action i.e send commands to the drive FB from the HMI.

Any advice inspiration would be gladly received.

If all of the drive data is in a consistent format then you could use tag multiplexing. Or you could use address multiplexing if only the DB number is to change between drives; you should be able to do that without a script.

"No-Scripting" sound like an odd requirement, maybe fear of the unknown which usually comes from ignorance.

Nick

Urm. Ok not used either of those before would have an example at all? Or a location where it is explained on a relevant website

From the Siemens web site:

Address multiplexing: http://support.automation.siemens.c...eus&objaction=cssearch&searchinprim=&nodeid99=

Tag Multiplexing: http://support.automation.siemens.c...eus&objaction=cssearch&searchinprim=&nodeid99=

I'll try and find some screenshot examples.

Nick

I don't know which HMI you are using. In Wonderware InTouch, for instance, you could accomplish the use of a common faceplate to access different PLC addresses by populating the faceplate with Indirect Tags and then assigning their linkage to IO Tags with a pushbutton script that opens the faceplate window, or on drive select pushbuttons within the faceplate window.

I'm not really familiar with the S7 PLC, but many PLCs also allow either indexed or indirect addressing, which would allow a fixed group of addresses tied to HMI tags to be dynamically redirected to different memory locations within the PLC.

The attached pictures show examples of tag multiplexing and address multiplexing in WinCCFlexible2008.

With the tag multiplexing, you create an internal tag for the value and then use another tag (internal or external) as the index value. In the tag configuration, each index value can then be assigned a different tag.

With Address Multiplexing, you create an internal tag for the value and then you can use other tags to specify the DB number, Byte number, Bit Number. In the example attached, only the DB number is specified by an internal tag.

Hope this helps,

Nick

Thanks Manglemender very useful.

We have gone down the route of using faceplates and extracting the required data by index moves into data blocks.