[?]: s7-300 plc programming

[seee]

hello dear friends.
one question has been in my mind for some years and i have not found an answer for it till now.
suppose you want to write plc program(s7-300)
for a new machine from beginning.
this machine have many cylinders,motors,valves and etc.
my question is that how you write plc program for each
part to avoid confusing?
Do you consider an fc for each part(for example:electric valves)?
In most of programs i have seen that the programmer
write whole cycle of machine in one fc and this fc communicate with other FCs. this fc called "sequencing".
how do you write plc program?
do you write sequencing program?
please please share your experiences.
best regards.

[gary_angel]

For this particular task, the best practice - define the identical parts in your machine(actuators, drives, sensors) and write
FB(Functional block) for each type.
Then "connect" this FB in according sequence using FC.

[Dfcz]

Every programmer writes as it is more convenient.
So write and don't worry, the main thing that would work.