S7 bytes to DInt

[sapoleon]

Hi.
I have a new project, and it's in siemens S7. I can say that I'm having a hard time, because it's my first project with S7.

In the project, I read a Cognex camera through Profinet, I get a result, that is a numeric code in separate bytes. So... It's like a string.

The thing is, that I have to send to an HMI this value like a DInt, and I don't have any idea on how to begin. I started looking for the IEC FC37 but it seems that I have to make a string out of the series of bytes that i get...

I get the bytes in PIB261 to PIB269 (always 9 cyphers).

I will appreciate if someone can point me in the direction on how to make a string from the bytes, so I can try the FC37 and convert it to a DInt.

Thanks.

 

[Bratt]

Create a new string in a datablock with 9 chars STRING[9] then you can simply move the data from the input area. You will also need to initialize the actual value of the string either you can write '000000000' in the inital and actual value of the datablock or write

L 9
T DB1.DBB1 //Byte containg current length of string

The first two bytes of a string contains max length and current length

Here i created a string named text STRING[9] in db 1

L PIB261
T DB1.Text[1] //If your string is named text

L PIB262
T DB1.Text[2]

......

CALL "STRNG_DI"
S :=DB1.Text
RET_VAL:=MD0

 

[L D[AR2P#0.0]]

Here's another example:

 

[sapoleon]

Thanks A LOT for the quick responses.

I see that i have to take into account 2 extra bytes in the string for max length and used lenght...

That is to say, that the string will be of 11 chars, but i still define it for 9 chars.

In the method defined by Bratt, how can I access the two first bytes of the string?

 

[Bratt]

Absolut Like DB1.DBB 0 // Max
DB1.DBB1 //Current

Or by using the pointer version like L D [AR2,P#0.0] described but then you need to write in stl format.

If its always nine chars you can create the datablock and write '000000000' in the inital and actual value of the string then you dont need to write anything in the length bytes. The 2 length bytes will always contain nine. Actually you only ned to write the zeros in actual value but its good to write it in the inital value aswell if someone decides to initziale the datablock in the future.

 

[sapoleon]

thanks again