Function Blocks??

How to Read an analog value like voltage, frequency using function block?

Wich plc-brand?

You can also do a search in this forum.

Schneider Modicon.
Also Can you tell how Modicon PLC addresses inputs that it wants to read through modbus.I know the command but Nobody is realy writing about the adressing format used?

inputvalue at %IW0:WORD;

in program you can make it real by WORD_TO_REAL
and then scale it according.
With a function block it is depending on what block you are using.
if you export the block i can tell you.

Modbus adressing are following :-
disrete :- 400001.0, 400001.1, 400001.2..
Analog:- 400001, 400002, 400003...

dipesh9486 said:

Modbus adressing are following :-
disrete :- 400001.0, 400001.1, 400001.2..
Analog:- 400001, 400002, 400003...

Click to expand...

discrete outs 000001, 000002 etc (also for internal coils)
discrete ins 100001, 100002 etc
analog ins 300001, 300002 etc
analog outs 400001, 400002 etc (also used for internal registers)

These are standard addressing, unsure if anything different for function blocks, not used them.

Addressing for Modbus and Schneider plc (and probably other IEC based plc address schemes)

PLC input bit %I - not accessible via modbus
PLC output bit %Q - not accessible via modbus
PLC memory bit %M - read/write through modbus 10000 address range (with a 1 offset)
PLC memory word %MW - read/write through modbus 40000 address range (with a 1 offset)
PLC input register %IW - not accessible via modbus
PLC output register %QW - not accessible via modbus
PLC status bits %S - not accessible via modbus
PLC status words %SW - not accessible via modbus