confused with Flag

am confused with Flag FD,FW and also about FY.
I have one program like this it is simatic s5 155u plc
:c db10
:l dd 180
:l fd 200
:T fw 200
:Aw
Can u please sir describ this program , line by line?.. it will be helpful for me

c db10 => call DB10 : work with Datablock 10
:l dd 180 => load data dubbelword 180 of DB10 into internal memory
:l fd 200 => load flag dubbelword 200 into internal memory
:T fw 200 => transfer internal memory to flagword 200
:Aw => and-word function

And-word

accu 1:0000 1111 1111 0000
accu 2:1111 0000 1010 1010
And-word
accu 1: 0000 0000 1010 0000

so how this FD 200 is getting value. Is there any fix value for FD200 or from some other area this FD 200 is getting the value?

FD200 must be getting it's value in some other part of the program. Use the cross-references to find out where this happens; block-number + segment-number.

Sir,
We are using siemens s-5 plc and already there are programmed by some professional. PLC is a very new system for me. So, sir i have some doubt..
Some time to bypass any or/ and logic we use F0.0 as logic 0 and F0.1 as logic 1. So, is the flag values contains constant values by default?.. if it is then how to assign the value of the flags?

Flags are 'low' by default at the start of the plc's first program scan. if you want a logic 1, you have to make this logic 1. Example by means of this program

and not flag 0.0 : AN F 0.0
set flag 0.0 : S F0.0

Thanks sir,
Today i got some programs in SB (sequence block).. Why is this Sequence block sir?. And sir please teach me in detail, How to make a FB and how to decleare the variables..
thanking you,
with regards,
pradip

SB's are used with sequential problems; here you can divide your program in logical steps. There is an other reaction depending on wich step you are in. example

step1: start machine 1
step2: start machine 2 5s after step1
step3: start machine 3 5s after step2

between steps there are transition-conditions e.g. did machine 1, 2 and 3 start, is the timer finished.....ect.

FB's.....mmmh without the software this will be not so easy because it has been a while since i did this....let's see.

To start; make a block like any other block only name it FB1.

Then you can give a name to a variable, maximum of 4 characters.
After this you must declare if this is an input-variable for your FB, or an output, or timer, counter, ect...you will see a list of possible choices....in S5 you will see a list e.g. E/A/T/C mind you an input-var can be: input, output, merkers...

Then you must declare if this is a bit, byte or word

You must program the FB in AWL

By the way...if you have totaly no experiance with S5-plc's, maybe better if you try to follow some lessons.

Thanks sir,
Is there any study meterial on internet for s5 plc?.. and sir what are the # flags?

For manuals you can take a look at the siemens website.


What do you mean with '#'? If this is somewhere inside a ladderdiagram this means the same like an output-coil. If you want to know the number of flags; this depands on the cpu.