Dynamic call of variable in datablock

Hello aganin.

I am trying to set a variable in a datablock, and I don't want to use direct adressing...

L #P_nr
OPN DB [#Temp_Int]
T [#CC]

So I want to place the P_nr [Int] variable in (if Temp_Int = 2) DB2.CC so to speak.

Is there any possible solution for this problem? or do I have to use something like:

L #P_nr
OPN DB [#Temp_Int]
T DBW 3 //CC is currently located at byte 3

/Thanks

One way would be to use AR1 and load it from your input parameter or calculate it. I don't know where #CC comes from, but for the moment let's assume it has a 3 in it. Your code would look like this:

L #CC
SLD 3
LAR1

L #P_nr
OPN DB [#Temp_Int]
T DBW[AR1,P#0.0]

But you may want to get more familiar with S7 first. It is very odd to want to write to DBW 3, although you may have a reason to do so.

Thanks for the qiuck reply!

Although I'm sorry I don't think I made myselfe clear enought.

CC is a variable in DB2 witch is placed at DBW2 (or +2.0) as it says in the "DB view" (Wrote DBW3 before, that was a missprint).

Again

Hello again. I'm sorry to take this up again, but I really need an answer to this...

So let's say I have a DB100 ("SysVars") In which I want to change a value at the variable "ProcDoneX" where X is a int from 1 to 10. Let's say that the variables is int's placed in the DB at +2.0 to +20.0

Now I know how to solve this with static mem handling and pointers i.e. to point at place 4.0 for Proc4Done, but is it possible to solve in any other way? How I foremost would like to solve it is just by SysVars."ProcDone" + inVar
(Ok that wouldn't work in any language i ever heard of, but I hope you get the point!)

/Thanks

Is this what you want to do in pseudo-code ?

SysVars.ProcDone = SysVars.ProcDone + inVar ;

No it's more like

SysVars.ProcDone[inVar (or i or whatever)] = anything, true for example.

Unless you use SCL, you are stuck with indirect addressing. One option is to use functions that read/write to an array, Here's some examples:

http://www.plctalk.net/qanda/showpost.php?p=239628&postcount=4

http://www.plctalk.net/qanda/showpost.php?p=252596&postcount=20