Scope of a local variable in a FC

Hello everybody,

I have a FC, where I have some Local Temp variables, one of this is used in a "strange" way , in my opinion.The code looks like this:

Network1:

L db1.dbb0

T#DINT_00

 
then after some networks,

Network30

L db2.dbb0

T#DINT_00

 Now, Most of the times the two bytes DB1.dbb0 and DB2.dbb0 have the same value, and in this case everything should work well, but when I will need two different values, don't will I need two different TEMP variables, like

L db2.dbb0

T#DINT_01 

or I'm wrong?

In the end, the scope of a local variable is ONLY inside whole the FC, or just inside the network?

Thanks

hi sbartoc,

it depends on how the variable is used after you gave it a new value. 

when you don´t need the value from DB1.DBB0 after Network 30 in your temp-variable, you can write an other value to it. 

a temp- variabel is valid until the block ends.

hope this helps,

regards,

Hi mopS04,

The two values are using for standby of two different conveyor belts. That's why I was wondering me, If I need two different standby times, Do I need two different temp variables ?

The values are never overwritten, just the operator can edit them.

hi sbartoc,

you can use them in that way you showed us. 

But when you changing something that belongs to conveyor 1 relating to this temp-var it has to happen in the code before it will be written again.

                //  temp is undefined

L DB1.DBB0      //  = 5     (for conveyor 1)

T #temp

...             //  temp=5   (sequence for conveyor 1)

...             //  temp=5   (sequence for conveyor 1)

...             //  temp=5   (sequence for conveyor 1)

L DB2.DBB0      //  = 7     (for conveyor 2

T #temp

...            //  temp=7    (sequence for conveyor 2)

...            //  temp=7    (sequence for conveyor 2)

...            //  temp=7    (sequence for conveyor 2)

hope this helps,

regards,

OK,

So it's as I said. It works just with one var temp, if the two standby have the same time. While , in order to work with two different times, we need one more var temp.

Last question,

The operator edit one of the standby  time, for example the DB2.dbb0 , the one in the network 30( e.g 30 seconds while DB1.db00 is 20 seconds) . When the conveyor belt will go into standby(assumed there are the conditions)? After 20 or 30 seconds?

Doesn't change twice each scan, the #temp variable?

Hi,

I don't completely get what you mean, I just got that is not a problem write twice each scan a local variable.

Can you explain me again with an easier example, please?

New question published by theoulis7 is split to a separate thread with the subject Mask FC doesn't set variable.

Best regards
Min_Moderator