working principle of analog inputs or outputs in siemens plc.

Can anyone tell me entirely about the working principle of analog inputs or outputs and data blocks in siemens plc.

Can you be a bit more concise about what exactly you want to know, it's not really very clear?

Analog inputs and outputs read or send an INT value to the hardware (PEW and PAW in German, not sure about English equivalent) in the range -27648 to +27648 for -10V to +10V for example.

Data blocks are parts of a memory area where you can store data, not unlike Merker (or Marker) memory, but more organised. Instance Data blocks are a special variety of Data blocks which are tied to particular FBs.

If you can frame your question a bit better, we can provide more informative answers - OK, I'd be totally lost trying to post a question in a Turkish forum!

first of all thanks for your interest.
for example if you have an sensor with 0-10 volt and youwant to process this sensor input in plc can you the all program step by step
thanks..

I'm sorry, but I'm still not entirely clear what you need.

However, on the assumption that you have a 0 - 10V input that you want to process, let's suppose it's PEW256:

first you need to read the input, the input is an INT value, for a typical S7 300 card for 0 - 10V it would be a value from 0 - 27648, this applies to most S7 300 cards, there may be other ranges for other cards, in particular for S7 400 series cards, with which I have no experience.

You can then either use this value directly, or you can scale it to engineering units for output to an HMI, for example ProTool or WinCC, by using the FC105 "Scale" function out of the Standard Library functions, if I remember rightly the sub-directory is the "TI to S7 conversion" sub-directory, or something similar, I'm not in the office now and don't have Step7 available.

Are we moving in the right direction here? If so, or even if not, we can continue tomorrow when I'm back in the office.

If you're lucky, some of our American friends, who will be about a bit longer may expand on this.

An analog signal, current or voltage, is delivered to an ADC (Analog to Digital Converter) in a PLC Card or Module.

The assumption is that the analog signal is proportion to some particular condition (PSI, GPM, FPM,... whatever).

The ADC converts the analog signal to a digital value. This value is dependent upon the range of the ADC. This range does NOT have any obvious, direct relationship to the particular condition being monitored.

The range is dependent upon the type of transmitter (-10V to +10V, or 0-mA 20-mA, or 4-mA to 20-mA,... etc.). This value is NOT Engineering units. Rather, it is proportional to the range of the ADC. This is generally called the "RAW" number.

Typically then, there is a SCALER function, somewhere in the PLC, that takes the "RAW" number and converts it to Engineering units (PSI, GPM, FPM,... etc.).

Typically, the process then depends on the converted Engineering Values to make decisions.

However, if the developer chooses to do so, the process could then use the RAW Numbers to make decisions.

That is, if the developer decides to do so, he can use the RAW Number to make decisions (which are harder to interpret while trouble-shooting... this is how it was done before the SCALAR routines were developed) or he can use the Converted Engineering Numbers (which are much easier to trouble-shoot... because the nature of the particular value is much more obvious).

There ya go... the rock-bottom basics.

ok
looking forward to hearing from you
thanks