slc5/04 timming problem

hi all,,!
i want to share a problem that i have editted programme but i face problem that after 2 t03 months timming issue accurs. timming of other pnemautic cylinders change which causing mechnical problems in machines.

so what am i doing wrong,,!

thnks n advance,,!

Can you please post your program ?

From your post i am assuming that you are using timers to control a machine with pneumatic cylinders.

if that is the case, i am afraid that you will always have problems and here's why. system parameters change, not your program, but the mechanics.

valves stick and get replaced.
cylinders have a higher friction rate (sticktion) when they are new.
the air quality changes.
air flow valves change and always get adjusted because the machine does not run fast enough.

if indeed this is the case, you need to add sensors to the cylinders to confirm the position.

regards,
james