Step-7 programming

A

Thread Starter

Aqui

Hello:

I have been working with a s7 314IFM CPU (v1.1) and STEP7 (v5.x).When I have tried to use standard function SCALE (FC105) it does not recognize the first parameter as valid if I put the integrated analog input PEW128.

(tested with W95 and NT)

thanks a lot
 
A

Andrew Hawdon

Hi
The problem is that you are using German addressing when you have Step 7 set up for english. E is an input (I) in German. If you use PIW128 you should have no problem.

Andrew
 
Z

Zan Von Flue

hi
I personally just gave it a try and it worked.
give it a try in OB1.
Start OB1
write-
CALL FC105 - the compiler should complete the call with
CALL FC105
IN :=
HI_LIM :=
LO_LIM :=
BIPOLAR:=
RET_VAL:=
OUT :=

If not the FC105 function, from the library/TI-S7 area, has to copied into your progect area.
Then next to IN, write PEW128 and (enter). It should go from red to black letters. If not maybe a higher service pack is needed, I have SP3. However I doubt this. If you put the mouse on IN, it should respond with IN:INT xxxxxx. Try it with MW2 (or 4...) for a test. Or !recopy! the FC from the library.
Later
zan
 
hello,
the fc105 can not use in cpu314ifm, it can only use in s7-400 cpu. you can read the help file in the step7 v5.1 .
This function is only used to convert the FB30 of an existing S5 program of an S5 CPU 928B, 945 or 948 to a function of an S7 program for the S7-400 programmable controller.
 
S

Shahid Waqas Chaudhry

You have probably defined Symbols for the Analog Inputs.
Here is how you can come around:
1) Delete the name from the symbol table
2) Enter the block (FC105) with all the variables.
3) After you have completed you block assignment, Give the analog input a
symbol (go to the in parameter, then press Alt-Enter for the Symbol
defination box).

btw, also check if you are using Internation or SIMATIC Pneumonics (SIMATIC:
PEW, International: PIW).

Hope this helps,

Shahid
 
D

Donald Pittendrigh

Hi All

Position your cursor on the block call and push F1 to see the help file for this FB, I think it says that it is only provided for conversion from S5 programs to S7 programs and is in fact not functional. It is so easy to process analog inputs in S7 that this function block is hardly justified anyway, If you take the analog input and divide it by the maximum range and then multiply it by the scale of your desired output, then you will have the same result with full control over how it is done, the logic fits into one segment in FBD and is very neat and easy to read in status, give it a try.

Cheers
Donald Pittendrigh
 
Thanks for tour suggestion but... I´ve tried it and gives the same result. Somebody said that it works only with S7-400( ??? )i have to check this (strange)

Thanks a lot


Aquilino

 
D

Dobrowolski, Jacek

Hello:

What is the serial number of that PLC (6ES7 314-5AE ... ) ?

Regards,

Jacek Dobrowolski, M. Sc. E. Eng.
Software Eng.
 
Z

Zan Von Flue

hi
I gave it a try yesterday on a 314ifm and it doesn't work. I tried other experiments with it on a 314ifm and couldn't get it to work.

later
zan

 
P

Piotr Kowalski

Hello!

I found 3 matching items in Siemens catalogue:

6ES7314-5AE03-0AB0 SIMATIC S7-300, CPU 314 COMPACT IF MODULE WITH MPI IF 16
DI/16 DO, 4 AI/1 AO INTEGRATED 24 V DC POWER SUPPLY 32 KBYTE WORKING MEMORY

6ES7314-5AE10-0AB0 SIMATIC S7-300, CPU 314 IFM COMPACT MODULE WITH SLOT F.
MC 16 DI/16 DO, 4 AI/1 AO INTEGRATED 24 V DC POWER SUPPLY 32 KBYTE WORKING MEMORY

6ES7314-5AE83-0AB0 SIMATIC S7-300, CPU 314 FOR EXPANDED TEMPERATURE RANGE
INTEGRATED 24 V DC POWER SUPPLY 16 DI/16 DO, 4 AI/1 AO 32 KBYTE WORKING
MEMORY

Kind Regards
Piotr Kowalski
 
D
The correct solution for FC105 is as follows:
make a reference to your analogue input in the symbol table, you will notice that the default Data type given is WORD, change this to INT, then save the symbols, enter your call to FC105 and type in the address e.g. PIW288>

 
D

Donald Pittendrigh

Hi All

If there was no symbol table entry then the block would have accepted the entry of PIW??? at FC105 however if it is wrong, it won't be accepted as a
parameter until corrected as explained.

Bye
DP

 
hi

i am working on step 7 PLC and i would like to have a protocol for communicating with it by programming.


regards,
vikas
 
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