How to use OPN DB [#number] and A DBX100.0?

fritz

Hi DanF5

If your Logic is an FC, you can easily have a second DB open by using the second DB register (aka DI register) for this as below:

L     MW   100
OPN   DI [MW 100]    // open DBx via second DB register
L     DIW    0       // load DBW0 from DB that is open via the second DB register
T     DB1.DBW    8
L     DIW    2
T     DB1.DBW   10
L     DIW    4
T     DB1.DBW   12
etc.

Tread with great caution though if you have your logic in an FB as the the DI register is automatically used to open the FB's Instance DB as well as any multi Instance offsets.

 Dear fritz,

I use S7-1500 I would like to use OPN DB[#number]

and A DBX100.0

       = #bit0

How to do it please ?

------------------------------------------------------------------------------------------
Split from OPN DB in STL issue.

OPN   %DB1

A     %DBX100.0

=     #bit0

DB1 would have to have "Optimized block access" turned off.

Please view the attached pictures for reference.

Best Regards,

AnJ_Automa

 

OPN   %DB1

A     %DBX100.0

=     #bit0

DB1 would have to have "Optimized block access" turned off.

Please view the attached pictures for reference.

Best Regards,

 Dear AnJ_Automa,

I mean how can do

L #DB_Number

A     %DBX100.0

I see. Then you will have to have some intermediary variable to store the variable number. A temp variable would suffice. However, to make this work you would have to have "Optimized block access" turned off for the FC you which to have this functionality.