(Beginner question,step7) Data addressing

kahorn03 · Jul 10, 2006

Hi!
I'm quite new to step7 and I'm not sure if I got this one right so I appreciate if you can help me out:
What does following addressing mean; DB11.DBW35 4(4 is underneath first addressing).
I've read that it should mean; Datablock11.Dataword35 ...(but what does the 4 stand for)?

SimonGoldsworthy · Jul 10, 2006

Where were you reading this from ?

kahorn03 · Jul 10, 2006

I've read it in the help manuals: Help>Content>appendix>memory areas of step7 cpu>system memory>using the system memory areas.

Have I got it totally wrong?

SimonGoldsworthy · Jul 10, 2006

If I look in the help area you mentioned, I see a table showing how to access the different areas. There is no mention of DB11.DBW35

(Which version of Step 7 are you running ? I am using V5.2 + SP1)

Gambrinus · Jul 10, 2006

DB11.DBW35 4 cann't exist. It's a mistake. Word access: DB11.DBW35
Bit access: DB11.DBX35.4

kahorn03 · Jul 12, 2006

You are right gambrinus.
The address appears to be DB11.DBW354 (just with a linebreak in between 5 and 4 which confused this newbie).
I am using v5.3+SP3, and in this version it is described DB and DBW separately.
Thanks for your help!

kahorn03 · Jul 12, 2006

Hi.
Given the success of my last question I shoot again:
The in wire in a Move block is addressed; "L#0".
Does this mean "Load 0"?
In other words when the EN/ENO is 1, the IN wire sets the out wire to 0?
Follow up: What does the "#" symbol do in addressing?
Examples: "#temp_real" in a Cmp-block and the "#0" in the move block.

PeterW · Jul 12, 2006

L#0 is a DINT (Double Integer, 32 bits long)

L 0 = Interger

L L#0 = Double Integer

# before a name means its a variable declared as a STAT or TEMP.

A #Start_up //could be either.

Some people give a clue in the name:

A #s_Start_up // means they declared it as a STAT, where

A #t_Start_up // means they declared it as a TEMP.

also

A -Start_Up would be and input, output or memory flag declared in the symbols files.

kahorn03 · Jul 12, 2006

Thank you!

dchartier · Jul 12, 2006

Hekko Kahorn;

When you see the # in addressing, it refers to the declarations table for FBs and FCs;

When you call the FB (as per this example) you will have to fill in parameters for it to transsfer to the local code.
#start := I12.4
#stop := Q23.6
#motor := DB100.DBX42.0
...

You can call the FB for another motor, and input new parameters for the code.
Every time you acall thisd FB in your program, you will specify the input and output parameters. This allows you to develop general code for say, a motor, a valve, a pump... then call this code for a specific instamnce of a motor, a valve, a pump...

Hope this helps,
Daniel Chartier

kahorn03 · Jul 12, 2006

Daniel Chartier, you made my day!
That was probably elementary knowledge, but it was crucial for me to understand this program I'm reading.
So thanks alot!
However, the #temp_real that I was refering to isn't in the referance data/symbol table. Is the symbol table and the table you mentioned two different tables??
If it is; where do I find it?

PeterW · Jul 12, 2006

At the top of the block that #temp_real appears in, if the declarations are not visible pull it down with the mouse. You will almost definately find it in the TEMP field as shown below:

The TEMP's are after the last range in both FB's and FC's.

If the programmer had not entered the symbol somewhere it would not display correctly and be red, the block would also not save when errors are there.

kahorn03 · Jul 12, 2006

Thanks for quick reply Peter!
You are right!
Eureka!

(Obviously it would be red, I dont know what I was thinking when writing that...)
I edited my post hoping that no one would have read it, but obviously you were to fast for me

Now Im going home, to cool down my brain, and then study this program some more.
Thanks everyone for your help!

kahorn03 · Jul 13, 2006

Hi!
This question is a little off-topic;
What is the point in using memory bits which is always 0 or always 1.
I have a paralell circuit in this program, where one memory bit in one of the branches is addressed "M1.0 always 0" in a normally open switch. This makes no sense to me as this branch of the circuit always will be 0 as a result of the memory bit...obviously I must be wrong, but what am I missing out?

PeterW · Jul 13, 2006

Its a little trick of programmers to disable or override things. Searching for those markers later on makes it easier to find the things you forced on/off.

(Beginner question,step7) Data addressing

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