Parameter to select the type of photocell:
NO photocell: contact opens if the beam is free. The
contact closes if the beam is interrupted. The shock,
photocell and open door contacts must be wired in
parallel.
NC photocell: opposite of the NO photocell. The
shock, photocell and open door contacts must be
wired in series.
NOTE: The shock, photocell and open door contacts
must all be of the same kind (NO or NC)