Hey Chris,
thank you for the information!
Yesterday I went through lots of Siemens manuals just to find out that it gets
the more confusing the deeper you go into.
Could it be that the P denotes a Pointer?
Because the "#" is usally used for symbolic addressing when I remember
correctly.
My aim is to have a clear and good syntax which is as TIAesk as it could be but
on the otherhand easy to understand for all non TIAlers.
So for me the addresses read like pointers to the start bit (DBX).
This probably makes sense as a String is not considered an elementary type in
TIA (as its larger than 4 bytes).
So the combined syntax would be:
P#DB1.DBX314.0:STRING
Or
P#DB1.DBX314.0:STRING[100]
With explicit length information.
A related question is, how does TIA handling referencing to arrays (I think we
agreed to do this as part of this string here).
Can anyone with TIA access (chris?) check how tia handles this?
Or should we simply make it similar with
P#DB1.DBX314.0:LREAL[10] // Read 10 LREALS starting at offset 314
What do you think?
Julian
Am 03.09.18, 09:47 schrieb "Christofer Dutz" <christofer.d...@c-ware.de>:
Hi Julian,
so I spun up my TIA and did some String stuff ...
Defined 2 Sting variables:
Name: Data type: Offset: Start value:
Hurz1 String 314.0 'Der Wold, das
Lamm"
Hurz2 String 570.0 'Auf der grünen
Wiese"
After compiling the memory block (DB1), the offsets were automatically set.
Then I added a CONCAT function to my PLC program and referenced those two
fields as input. Here's what TIA made out of it:
Hurz1: P#DB1.DBX314.0
Hurz2: P#DB1.DBX570.0
Notice the "P#" instead of the "%"? And it seems that the address looks
like a BIT address, as it has the bit offset part set. But just comparing this
to all the others, it seems like all types can have a bit-offset part set, this
is just always ".0" for any non-bit type.
Chris
Am 02.09.18, 13:03 schrieb "Julian Feinauer" <j.feina...@pragmaticminds.de>:
Hey everybody,
I have another question about the semantics we should provide for
reading / writing Strings in the S7 Driver.
I have not found an example on how this is handled currently but to me
it looks a bit like a mix of reading the data as “array”, i.e., using the size
parameter on the request (= fixed size string) but handling it as null
terminated String.
As I have currently no TIA available, can anyone give me the syntax how
Strings are addressed in TIA.
I think they were fixed size always and I would prefer to do it that
way.
Could anyone who implemented this (or has expertise in this) help me
out a bit?
Thanks
Julian
