WinCC flexible Question

We are using WinCC flexible 2007 for HMI. In the project some external tags which are connected with PLC, but address is shown for example DB[Index] DBW36 . Could anyone please explain me what does DB[Index] means ?

It looks like an array.

Is index a Wincc tag defined as an array?

Hi
[Index] is a tag so if the value of tag index was, say, 2 the DB[Index]DBW36 would point to DB2.DBW36

Think of it as indirect addressing for the DB number

Cheers

Index is internal tag. Then how index get value ?

arocon said:

Index is internal tag. Then how index get value ?

Click to expand...

index value is either defined when you created it, or linked to another tag. there could be a script somewhere that gets the value of index. it is hard to say without the project file to look at. do you have any macro's, functions or such in the project?

How it could have been done:
Motor 1 use DB101
Motor 2 use DB102 e.g.

DB's have to be identical of course. at least regarding the indexed tags.

Use button
Set index
Call Screen with tags where index is included in the tag name.

Maybe "ActivateScreen" should be moved to Release, but is should not be necessary.
For some function you get a "free" delay between "press" and "Release"

Use cross reference to locate the tags usage

one of the main reasons I no longer will even try to work with step 7 or wincc

One FB can adress more than one DB (when you create a FB check for "Multiple Instance Capabilities"). For example,each motor has assigned a DB according with its characteristics but an FB can process many motors, differences are given by the associated DBs. One specific adress in the same DBs (base=point of start DB + deplacement= offset to base)point to the same parameter, with value determined by motor. Ex: DB2 and DB3 are 2 DBs assigned to motor 2 and motor 3, at adressses DB2.DW36 and DB3.DW36 you can find the actual speed of motor as parameter, but the values can be different (DB2.DW36=1200rpm, DB3.DW36=1500rpm).In the S7 program, in FB, you can select the DB you need witn instruction OPN DIx, in the lines below you use the instance DBx as supplying block for FB variables.