Hello,

I have experience using Step 7 V5.5 but am new to TIA Portal and would like some advice on a problem I have trying to use indirect addressing.

I am writing software for a customer using a S7-1214C DC/DC/DC CPU with TIA Portal version 14.  The application involves an operator selecting one of several "jobs" at the beginning of a production cycle.  The data for these I have placed inside a single DB, with each job as a data structure inside the datablock (see picture "job datablock").

I want to then transfer the selected job data to a working area when an operator selects that job.  This data area is in a different datablock and is the same structure as in the job datablock.  So, for example, when Job 2 is selected, I want to copy the contents of that data structure into the "Job_Work_Area" structure shown in the picture "working datablock".

I have considered a couple of ideas about how this could be done but I don't think they are valid.  The first was whether it was possible to use the job number to reference the correct part of the job datablock, for example:

"Job_Data"."Job_[MW4]  MOVE "HMI_Data"."Job_Work_Area"

where MW4 would be the selected job number.  I know this syntax is incorrect but I just wonder if this can be done in principle.

The other option was if the datablocks were configured as non-optimised DBs, whether I could use the selected job number as an offset to select a source address and then copy x datawords to the destination address.

I have looked at the MOVE_BLK command but I don't know if this is appropriate.  I know there is more that can be done using SCL instead of LAD but I have never used this language before (only STL in Step 7), so I am not familiar with it.

Any hints would be gratefully received.  I am sure there must be a way to do this but I have never used indirect addressing in TIA Portal before.

R Goodchild

P.S. The webpage would only let me add one file to this post, so I cannot add the screenshot of the working area datablock.

Hi!

You could create a PLC data type instead of using structs in a DB. Then you could create an array of that PLC data type in a DB.  Since SCL is in the TIA package, you can refer to an element of that array using a variable index (Int).

Kahl,

Thanks very much for the suggestion: that's exactly what I need and I thought there must be a simple way to do this.  

Rich.