DB instance of FB as datatype

Hello everyone,

is there any method how to make DataType instead of DB insatnce for FB?

I have FB for doors (some counters, timers, logic etc...)

With every instance of this FB it creates DB instance - but it's too many DBs so is here any chance / method how to make this DBs as a user defined data type and put it in single DB?

Like timers - i can make DB with IEC_TIMER datatype and use only one DB for all timers in program instead of plenty DBs.

Thanks!

Hello Cadej_Chudej,

what you're looking for is "Multi-Instance".

You create a FB (let's call it "gather" in this example) with the sole function to call your door-FBs inside.

This "gather" FB will have create one DB for itself once it's called.

Call your "gather"-FB in OB1 (or wherever you want to), call each of the door-FBs inside that "gather"-FB and create Multi-Instances instead of Single-Instances.

Now the DB of the "gather"-FD will contain your door-DBs.

Hope this helped!

Hello Cadej_Chudej,

you have to declare the instance DB as a static variable in a function block. See the example in the enclosed picture.

New question published by Abhiboss is split to a separate thread with the subject S7-400: DB instance of FB as datatype.

Best regards
Jen_Moderator