Hej everyone,

I created an FB to work with a Siemens V20 drive. The actual block that runs the V20 needs an instance DB. I would like to make an input parameter on my FB where I can fill in the DB number. 

The problem is that I don't know which datatype I must give this parameter to let it work. So shortly, How do you create an input parameter on an FB on which you can access a DB??

Greetings,

TheDuke

TheDuke.

I created an FB to work with a Siemens V20 drive. The actual block that runs the V20 needs an instance DB. I would like to make an input parameter on my FB where I can fill in the DB number. 

The problem is that I don't know which datatype I must give this parameter to let it work. So shortly, How do you create an input parameter on an FB on which you can access a DB??

- Which PLC?
- Which Step7 version?
- Which language?
- Why a number? .. why not call same FB several times each with different DB?

suggestion #1..
Use STL command "OPN" with indirect addressing inside the FB.

suggestion #2..
* Create a UDT that contains all the data as the FB would have
* Make the FB an FC with a single IN/OUT parameter of the new UDT
* Temporary memory and global applied states (Example: Global Run) stays in place as FB would have
* Create an array of the new UDT inside a global DB
* Call the FC as you like with an array element connected to it.

Example:
                                              _________
----------------------------------|       FC20
                                             |
 "DB_5".dataMotor[#Nr] - |   data
                                             |

w

I have a S7-1500 PLC and I use TIA Portal V13. The language is LAD.

This is a FB that I wrote myself. Inside this FB I call a USS_Drive_Control block which runs the V20 drive. It's this USS block that I need to give a DB. The problem is when you use aV20 drive multiple times, you must give all of the drives the same DB.

I want to put this block in a library for future use. Now I use DB6 but maybe later in other projects I want to give it another DB.  That's why I want an input where I can attach the DB that I like.

okay.. I think I understand what you need.

You need to create a DB inside a DB - - - also called multi-instance.
See attached picture.

w

No that's not what I meant. Sorry, my English isn't that good and the problem is quite difficult to explain I guess :). But here I added a ZIP-file. In this file you'll find images that will show you the problem;

The content of the map:

-DB_AbsoluteAcces (Current situation)

-DB_IndirectAcces1 & DB_IndirectAcces2 (My goal)

Thanks allready for your effort!!

Greetings

(smile) yeah.. it is difficult needing to talk in a language that is not your home language. (wink) English is also not my 1st choice. Don't worry you are doing fine.

I did understand what you want.
You want to make FB651 a library standard object.

Please believe me that what I suggest is the better solution.
The USS controller block do not have to consume its own DB (DB6).
The data that DB6 would carry, can be carried as part of your own code FB

Assume "FB651" is the code that contains the USS controller instruction.
Then you can have DB1001 linked to FB651 and DB1001 carries also the data of DB6.
Also you can have a 2nd call for FB651.. this time linking DB1002.
Again the data that would have gone to "DB6" is carried by DB1002 instead.

This is what we do when creating custom library code.. please trust me.

Try out what I suggested on a blank project... see what it does.

w

Can you explain a bit further? I don't fully understand your solution.

First I tried to give de USS_Drive block an instance DB (inside FB651) but this didn't work. We have 16 V20 drives over here and all of the blocks running these drives need to be linked to the same instance DB, in my case DB6.

In the part I understand your solution I see you're giving different DB's, that's confusing me.

See what you can do with the attached image.

Hi!

As I understand, you want your own FB inside which you call the USS_Drive_Control block.

You want to call your FB in multiple locations but want to use the same, single DB for the USS_Drive_Control blocks inside your FBs.

Is that correct?

Yes that is exactly what I need! =)