shared data-block

Greet · Aug 29, 2003

Is it possible to put a shared data-block in the Variable declaration table of a FB ?

I have a FB where I use the data of a shared DB, so I use the OPN DB instruction in my FB.

I have to do this four times for a different DB, but the instructions in the FB stays the same --> can I use one FB and four DB's? I use the DB's also in other FB's (that's why I've made a shared DB)

seppoalanen · Aug 29, 2003

Hi Greet,

If I understand, you are using S5-program.

Indirect DB opening working like this (German):





L  KF 10 ; LIKE OPEN DB10

T  MW 50 ; (FW 50 in english)

B  MW 50 ; NEXT COMMAND OPERATION PART USES MW 50 CONTENTS (DO in english)

A  DB 0  ; MUST BE '0', SO PROGRAM OPENS DB 10 (C in english)

You can use formal parameters as well.

br.Seppo

Greet · Aug 29, 2003

Thanks, but it is in S7 that I want to do that. So then I have to make a variabele table wher I want to put my DB in.

seppoalanen · Aug 29, 2003



FC ??



1s't split: Declarations



Address Declaration Name        Type

0.0     in          DB-Number   INT

2.0     in          DB-Word     INT 

etc... 



2n'd split: program



AUF  DB[#DB-Number]

L    DBW[#DB-Word]

etc.  





in FC ?? Call could be :



CALL FC ??

 DB-Number     :=50  -- selected DB-Number

 DB-Word       :=10  -- selected DB-Word

 etc..

rdrast · Aug 29, 2003

Question: Are you using an FB (Function BLOCK) or FC (Function CALL)?

If a function block, you can add a DB number as an input parameter, then just open it in the block to reference 4 different DB's.

If a function call, you can do the same thing, or you can pass actual structures in and out of the call.

Greet · Aug 29, 2003

it is in a Function Block that I want to call these DB's.

I tried it out, but it doesn't work: faultmessage: "no indirect operations for FB parameter DB-num". (DB-num is the name of my INT-variabele)

seppoalanen · Aug 29, 2003

Greet said:
it is in a Function Block that I want to call these DB's.

I tried it out, but it doesn't work: faultmessage: "no indirect operations for FB parameter DB-num". (DB-num is the name of my INT-variabele)

Try like attached.

seppoalanen · Aug 29, 2003

Greet said:
it is in a Function Block that I want to call these DB's.

I tried it out, but it doesn't work: faultmessage: "no indirect operations for FB parameter DB-num". (DB-num is the name of my INT-variabele)

Try like attached.

rdrast · Aug 29, 2003

I guess I'm just now sure of what you want to do.

If you want to use a function block, and only one block, to control several different devices (ie. motor starter block), you can make it multi-instanced.

The example Seppo gave is for a function call, I'm not sure right now if that is applicable.

seppoalanen · Aug 29, 2003

Thanks rdrast.

Personally I don't use FB-programs if it is not necessary. It needs own DB-block(s). In this case, I think FC-block is enough, where flexible indirect DB-Number can be one input-parameter in FC-CALL.

shared data-block

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