O
P
T
O
-
D
T
• DT1 #552 • DT3 #553
Emitter
diagonally across the track.
for alignment, shoot the beam
246 W. Main St.
Leola, PA 17540
(717) 661-7041
www.dallee.com
OPTO-DT - INFRA-RED OPTICAL DETECTION
The OPTO-DT is a detection device in which the output relay
(DPDT - Double Pole Double Throw) is activated when the optical
path of an infra-red beam is interrupted. An additional version
allows up to three separate infra-red beams activating the same
relay.
The electronic circuitry must be powered by a regulated 12 volt DC
supply (see our 12VPS, item 369) in order to function properly,
failure to do this will destroy the electronics.
The infra-red beam is generated by an input set (optical coupler)
consisting of an emitter (looks like a clear, tinted, LED) and a
detector (looks like a black LED). The emitter and detector are
mounted on the layout so as to establish a line of sight beam
across an area where detection is desired. The emitter and
detector can be separated by more than 6 feet but must be
precisely aligned. To assist in this alignment, there is an LED on
the OPTO-DT which illuminates when proper adjustment is
achieved. The version with multiple inputs has switches so that
each emitter/detector set can be independently aligned.
The OPTO-DT can be set for two distinct time functions. In
NORMAL function, with the time adjustment at minimum setting,
the relay will be activated (on) when the infra-red beam is
interrupted and relaxed (off) when the beam is restored. As the
time adjustment is increased a minimum (on) time for the relay is
established. When the beam is broken the relay is (on) for at least
the minimum time period. If the beam remains interrupted beyond
the minimum time period the relay stays (on) until the beam is
restored. In TIMER function, when the beam is broken, the relay is
(on) for the duration of the time adjustment, then relaxes (off). The
relay will not again activate until after the beam is restored which
will allow the circuit to reset. This time adjustment is variable from
momentary to about 60 seconds.
Each OPTO-DT is furnished with the appropriate number of optical
couplers.
Detector
Upper Left -
Relay Output &
'+' input power
#6 mtg.
screw
pads for
exp. relay
sect. A
1| 2 |3 | 4
Lower Left -
Relay Output &
'-' input power
Relay sect A: 1 - N/O
wiring diagram
Selector Switches - DT3
Jumper block - DT1
Upper Right -
1| 2 |3 | 4
sect. B
Time
Adjust
Lower Right -
2 - C
3 - N/C
Optical emitter outputs
#6 mtg.
screw
1| 2 |3 | 4
Optical detector inputs
LED -
Alignment Indicator
Relay sect B: 4 - N/O
3 - C
2 - N/C
1| 2 |3 | 4
INST ALLATION & OPERATION
The OPTO-DT has two sets of terminal strips which are used when
installing the OPTO-DT for operation. The first set is used for the
connections to the relay contacts and the 12 volt regulated DC
input power. With the relay positioned to the left of the circuit
board and the alignment LED at the lower right corner, the
connections to the left terminal strips are as follows:
Upper terminal #4 and Lower #1
Normally Open contact .......... when relay activates this
contact is connected to the
common contact (N/O).
Upper terminal #3 and Lower #2
Common contact ................... switches between N/O & N/C.
Upper terminal #2 and Lower #3
Normally Closed contact ....... this contact is connected to
common, except when the
relay is activated, the contact
is disconnected (N/C).
Upper terminal #1 : ( + ) connection from the 12 volt DC power
Lower terminal #4 : ( - ) connection from the 12 volt DC power
Note: Reverse polarity of the 12 volt DC input power or not
using 12 volt regulated DC will damage the OPTO-DT
and will not be warranted for consequential damage. All
connections should be done with the power OFF and all
wires should not be stripped longer than 1/8" so as not to
allow shorting to occur to the circuit board tracks at the
barrier strips on the printed circuit board. Wires are to be
stripped and placed into the open hole, then the screw is
to be turned CW until the wire is clamped into the barrier
strip. Using too small of a gauge of wire or solid wire will
not produce a proper connection.
hood is nearly impossible). The actual distance will depend on
conditions within your layout area and on how precisely you are
able to align the emitter/detector set. To shield from sunlight in
outdoor type layouts, place the receiver inside a house or
building with the interior painted flat black to avoid reflections.
Then mount the detector far enough back so that the sunlight will
not strike the detector and yet leaves a straight line of sight to the
emitter.
After mounting the optical devices and making all electrical
connections to the OPTO-DT board it is time to power up and
check the alignment of the optical path. When the alignment is
correct the small LED in the lower right corner of the board will
illuminate. Alignment is accomplished mechanically by bending
and rotating the mount brackets. The further apart the optical
devices are mounted the more critical precise alignment
becomes. Take your time and have patience.
The multiple input version of the OPTO-DT has a block of four small
rocker type switches which are used to change functions.
Switches #1, #2 and #3 are for selecting and aligning the optical
sets. If you are using less than three optical sets with this
OPTO-DT, the switch for the unused set must be in the open
position. For adjustment of alignment, turn the selected switch to
the closed position and leave the other two switches open. This
will allow each of the optical sets to be independently selected for
alignment. When alignment has been completed, return the
switches for the optical sets to their closed positions which is the
normal position for operation.
Rocker switch #4 is used to determine which time function is to be
selected. When switch #4 is closed the NORMAL function is
operational. In NORMAL function, the relay is activated when the
optical path is interrupted and relaxed when the optical path is
restored. There is a time adjustment potentiometer located above
the relay, adjacent to upper left terminal #1. Full counter
clockwise rotation of this potentiometer corresponds to minimum
The second set of terminal strips, to the lower right, are used to
connect the optical input sets (optical detectors, black units). The
copper wire of the detector connects to terminal #1 and the silver
wire connects to #4. In the multiple version the copper wires from
the second and third detectors connect to #2 and #3. All silver
wires from the detectors connect to terminal #4. These should
not be connected in reverse polarity since damage to the
detectors may occur!
The upper right strip is for the emitters (clear). The copper wire of
the emitter connects to terminal #1 and the silver wire connects
to terminal #4. In the multiple version the emitters must be
connected in series. The copper wire of the first emitter connects
to terminal #1, silver wire connects to the copper of the second
emitter (#2), whose silver then connects to the copper of the third
emitter(#3). The silver wire of the last emitter always connects to
terminal #4. These series connections can be made at the #2
and #3 terminals as indicated above or directly, wire to wire, at
the layout location.
The emitter/detector devices are supplied, mounted on brackets,
with wires attached. When attaching these brackets to the layout
please use screws and care so as to minimize physical damage
to the devices. To extend the distance between the emitter and
detector it will be necessary to lengthen the wires. When
extending these wires it is absolutely essential that the polarity of
the connections from the emitter/detector devices to the
OPTO-DT board be maintained. If the polarity is reversed the
optical devices will be damaged. It is suggested that when
possible only the emitter wires be extended. If you must extend
the detector wires, do so sparingly as extra wire length may
reduce the sensitivity of the detector. Also twist the wires to
reduce outside electrical interference. As a further aid in
extending the optical range a hood or shield can be installed on
the detector. A short length of tubing, heatshrink is ideal, makes
an excellent hood (this is only required if alignment without a
(momentary) time setting. Rotating clockwise will increase the
time setting to a maximum of about 60 seconds. With the
OPTO-DT in NORMAL function, this time setting establishes a
minimum on time for the relay i.e., when the optical beam is
interrupted the relay is activated for the minimum time or for the
duration of the interruption, whichever is LONGER. If switch #4 is
open the TIMER function is selected. In TIMER function, when
the optical path is interrupted, the relay is activated for the set
time period and then is relaxed. The relay WILL NOT ACTIVATE
AGAIN until the optical path is restored which will allow the circuit
to reset.
The OPTO-DT with only one input set has a jumper bar in place of
switch #4. NORMAL is selected when the jumper is closed while
an open jumper sets TIMER function. DO NOT place this jumper
across any other connector!
The output relay of the OPTO-DT is of Double Pole Double Throw
configuration with contacts rated at 5 Amps. There may be
situations where you may desire to have additional relay contacts
available. At the left edge of the OPTO-DT board, just above the
lower left terminal strip, there are two pads on the board. These
pads allow for a second relay (Item #555) to be operated by the
OPTO-DT. This 'piggy back' relay is furnished on a mounting
board with terminal strips. T o connect, carefully solder two small
wires to the OPTO-DT boards pads and then place the wires into
the appropriate "RC" barrier strip connectors on the relay board.
When soldering, only use a small pencil iron with Rosin core or
other appropriate solder for electronic equipment! Other types of
solder and fluxes will destroy the board.
When power is first applied to the OPTO-DT the relay will energize
for the duration of the selected time cycle.
rev 1, 2003
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