Cardin Elettronica PRG303 Manuel D'utilisation page 13

OPERATING WITHOUT TRAVEL LIMITS
The system is designed to operate without mechanical closing travel limits; the work time
management allows the system to control the position of the garage door. The following
points however should be taken into consideration:
1) Due to climatic variations or mechanical wear the performance of the system can change.
A work time programmed without leaving a margin of tolerance (extra time) may not be suf-
ficient to complete the manoeuvre (in other words, over a period of time the shutter may
remain slightly open). To avoid this situation proceed as follows:
1a) during programming keep the motor under tension for a couple of seconds after the
opening cycle has terminated.
1b) the programmer automatically allows for a 3-second increase in order to guarantee that
during repeated travel direction inversion manoeuvres the forcing movement of the shutter
does not cause this problem.
Example: with the shutter completely open
Command sequence: the shutter closes for 1 second then opens
Result: the shutter moves in the closing direction for 1 second and in the opening
direction for 1 + 3 seconds, so the motor remains under tension for 3 seconds
after the shutter is completely open.
If this situation causes problems to the structure of the shutter an opening travel limit will
have to be installed. The problem does not exist however for the closing cycle because the
shutter is completely closed after the manoeuvre.
2) During blackouts the programmer will lose the position of the shutter and the following
situations will occur:
2a) without travel limits (or with inactive travel limits) the shutter is considered to be com-
pletely closed.
2b) with an active closing travel limit you will have the exact position of the shutter.
Attention! To enable this situation; when the system is restarted with the shutter not com-
pletely closed the motor will be kept under tension (for longer than normally necessary)
during the first cycle. This remains valid until the cycle has been completed and the shutter
is completely closed. At this point the programmer will once again know the exact position
of the shutter.
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