Excel to S7 DB using kepware DDE /OPC

[cjd1965]

Hi I recently saw an AB/Rockwell guy using a excel spreadsheet of config data which he could read or write to a plc via opc. Anyone got an example or technote of this for S7? I think it would be very handy for assigning parameters for my equipment DB's (valves, pumps etc)

I would be using the MPI adaptor if that makes any difference

Every search seems to be how to read S7 data inside excel but writing is more important to me

Cheers.

 

[Fred_Loveless]

E-mail Kepware Support and ask them for the DDE Connectivity guide for KEPServerEX V5. They can get it from someone in the Customer Solutiosn team. DDE is not promoted because it is no longer actively supported by Microsoft and can be difficult to use in the newer OS's

 

[TheStarr]

Check out this link: http://www.plcdev.com/connecting_controllogix_excel

It is AB stuff, but I am pretty sure that the Excel to the server portion is basically the same.

Also try looking up the "DDEpoke" command.

 

[cjd1965]

Thanks I will check out the link. Fred if dde is old hat what is the “new thing“

 

[TheStarr]

I am sure Fred has better info, but...

First, we are an AB shop, but I still wanted to give my opinion.

The new thing was OPC. Third party software like Kepware acts as a translator between different applications.

Although, you need to take into account the timing issues with any third party software.

Example: You have a trigger tag to tell you when to read a string, call it "Trigger". So Trigger goes high and you immediately read the string. Problem is that the string has not fully updated. So you either have to put a delay on the trigger or a delay on the read.

Depending on the load of the CPU, the timing changes. This can cause strange problems.

We have been using InGear by AB on all of our newer applications. This allows VB to directly read and write the PLC, no delay.

Not sure if the same thing exists for your system.

 

[cjd1965]

Thanks. Because it will be a one off task on every job I think it will be easier to write some vba to create a awl source file.
I have used opc for plc and hmi comms etc but not for excel to pc

Thanks

 

[Fred_Loveless]

The example that we provide explains how to do Macros and VBA code in Excel to do this.