The Model Train Technology™ DPDT LATCHING Relay Board™ provides a simple way to use the MTT Precision Sensor to trigger a DPDT (Double-Pole, Double Throw) latching relay.
The Latching Relay KEEPS its position after the detector is unoccupied. The Detector must be cleared (unoccupied) and then ANOTHER trigger pulse received for the relay to flip.
The latch DOES NOT change when power is turned off and does not use current to hold the coil. Current is only used momentarily to flip the relay and latch it.
This is different from the standard MTT DPDT relay that follows (mimics) the Detector input: ON/OFF following the state of the detector.
The relay board also remembers the state of the relay and will activate the onboard GREEN LED to match the relay state on power up- giving you a visual clue of the state.
Lastly, there are three ways to change the state of the relay:
- tripped by a Precision Detector
- push the onboard push button
- connect a SPST momentary remote pushbutton between the GND (center terminal) and the DETECT terminal.
When you press the button in either scenario #2 and #3, it will flip the relay. You may need to use this initially to get the relay (and turnout if applicable) to the correct state (CLOSED/THROWN) for your application.
There are many application uses but here are two:
- Reverse the polarity of the track for a back and forth trolley style automation or for a REVERSING LOOP. Im this case you want the track voltages to stay set even after the detector is cleared.
- Turn one or more Tortoise-style Turnouts (which require a DPDT to reverse the polarity of the motor) but you want the switch to stay in that position until another/different Sensor trips to turn the switch another way.
This relay circuit is purpose build for our detector and may not work with other sensor systems unless they have an ACTIVE LOW signal.
The relay contacts are rated to 1A.
Use the same 12VDC power source to power the Precision Detector and the DPDT Relay Board. You may connect the Precision Detector yellow signal wires to BOTH this relay board AND any Signal Controller in our product lineup.
