siemens plc s7 300

Search this forum after FC105 (Scale) and FC106 (Unscale), I´m sure you will find a lot of information about it. Not sure if the same blocks is avalible in Step7 Lite...Have never used that software but you can do it like this in the normal Step7.

FC105 lets you convert your analog input (i.e. PIW128) to a real value via the high and low limit.

The block "SCALE" is FC105 (You can find it under Standard Library -> TI-S7 Converting Blocks).

Here is an example:

CALL "SCALE"
IN :=PIW128
HI_LIM :=1.000000e+002
LO_LIM :=0.000000e+000
BIPOLAR:=FALSE
RET_VAL:=#RET_VAL
OUT :=MD10



IN = your analog input (lets say that its set for 4-20mA).
HI_LIM = Your highlimit, here set to 100.
LO_LIM = Lowlimit = 0.
BIPOLAR = If the signal should be bipolar, normally set to false.
RET_VAL = Here you can error information, its here set to be written to a temp word.
OUT = Here you receive your converted value.

So if you got 20mA in the example above you get 100.0 in MD10... And if you got 4mA you will receive 0.0 in MD10.

FC106 works the same way just backways =)

When using FC105 analog inputs (PIW) and FC106 outputs (PQW) shuld be set to INT in the symboltable.

Regards

/e :D
 
Depending on wether the CPU has a built in counter - you can use SFB48 "FREQUENC" Frequency Counter its quite straightforward and the help is useful.
 
Depending on wether the CPU has a built in counter - you can use SFB48 "FREQUENC" Frequency Counter its quite straightforward and the help is useful.


could you give an example since SFB48 have a lot of parameters/address to fill in, say I will use a CPU 6ES7312-5BDO1-OABO(Siemens)with 2 channel counting and measuring.
 
One question first: have you already read the manual? Have you even started to? It's the main error my students used to make. Once they had read the manual, or at least the help items for the concerned block, they suddenly had almost no questions left.

Regards,
 
I have done reading the manual....but just asking for an example since the manual doesn't have one...anyway if you find it hard enough to give an example, don't bother....thanks
 

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