problem with db0

Data blocks DB 0, DB 1, DX 0, DX 1 and DX 2 are reserved for special functions.
They are managed by the system program and you cannot use them freely for other functions

Marcjan

Hello,

In Step 7 you can't name a DB; DB0, numbering starts at DB1

Regards,

Marcjan

Navnag

Hello thomas.alfa

Which S5 CPU is being used in this program ?

Data blocks DB 0, DB 1, DX 0, DX 1 and DX 2 are reserved for special functions.
They are managed by the system program and you cannot use them freely for other functions

e.g. in CPU 948 - Data block DB 0 contains the address list with the start addresses of all blocks that are located in the data block RAM of the CPU.

The Blocks can be indirectly addressed using this list.

I have attached an Extract from the CPU 948 manual explaining the functionality of DB 0 , DB 1, DX 0, DX 1 and DX 2 .

Hope this helps

Cheers

Navnag

sps-concept

Hello,

you should send the code of FB230.

Regards

André Räppel

Navnag

Hello thomas.alfa

Is it possible to share the S5 Code ?
It would be possible to have a better idea in we see this in proper context

Cheers

Navnag

Navnag

Hello thomas.alfa

This is quite unusual to say the least .... if fact I am surprised that the STEP5 Editor is not giving any error in FB 230.

The Formal Operands "ZWDB" and "ARDB" have been used as Data Blocks inside FB 230 ( As they should be ) using a "DO" Command

However "MBDB" has been used like a value ( With "LW=" command ) as for "MBVB"

I have one theory ( Just a long shot ) that maybe someone by mistake changed the parameter type "MBVB" from Type Data "D" to "B" ... unless someone comes up with a better explaination.

I Just tried toEdit the FB 230 and changed the parameter type of "MBDB" from "B" to HexWord ( "D" "KH" ). When we do this, the Assigned value to FB 230 "MBDB" parameter in FB 45 is displayed as 2000hex

You can try this and see what happens.

In any case, a lot of the programming has been done using indirect addressing. You need to be careful about the same during S5 to S7 conversion ( More so because S5 uses Word addressing while S7 uses Byte addressing )

Hope this helps

Good Luck.

Cheers

Navnag

fritz

Hello thomas.alfa

There’s nothing out of the ordinary happening here as far as I’m concerned.

Have a good look at the logic inside FB230 and you’ll notice the following:
Segment 2: The value of Parameter “MDDB” is checked via FB232 to see if the DB number in it is 0. If so, F 243.0 will be 1.
Segment 6: If F 243.0 is 1 (i.e. “MDDB” has been assigned “DB 0”) the part of the Logic that would open and use the assigned DB is being skipped.

In other words: Using “DB 0” as the actual Parameter value for “MDDB” was done to informFB230 that this DB is not to be used for this call of FB230.

As S7 does not allow you to assign “DB 0” as an actual Parameter value anymore, you have a number of options to replicate this functionality, including but not limited to:
1.) Get rid of the “MDDB” Parameter altogether and adjust the converted FB230 accordingly (FB230 seems to be only called once in your program).
2.) Use a different DB number as the “MDDB not in use” declaration (e.g. change FB232’s check for DB number = 0 to for example DB number =777 and assign DB777 instead of DB 0 to Parameter "MDDB”).
3.) Change the “MDDB” Parameter from type “Block_DB” in the converted FB230 to for example type “INT”. Change the logic in the converted FB230 to suit and assign an INT value of 0 to the “MDDB” Parameter for the call of FB230.

I hope this helps