Construction and Operation
Download TCL/DOT LED Blank-out Sign in IP55/NEMA 3X Cabinet Specifications
- Frame Housing
- Slim line, single piece of extruded aluminum (6063-T5), that houses the polycarbonate, circuit board as well as the sign back.
- The extruded aluminum consists of a 2.5" depth.
- The length of the extrusion varies for each sign size customization.
- The corrosion resistant aluminum bends to the sign size and each end is secured together by an extrusion and screws.
- All components shall be placed to avoid drip points.
- All wiring shall incorporate drip loops and strain relief
- The cabinet shall have an electrostatically applied Duracon 5600RTS Heritage Bronze coating.
- The finish shall meet the following criteria:
- 16-22% Gloss @ 60°
- H-2H Pencil Hardness
- Dry film thickness 1 - 1.2 mils
- The back of the sign is .125 aluminum
- At the top of the back, there is a lip that is inserted into the extrusion.
- At the bottom of the back, there are two screw holes which secure the back to the extrusion.
- Standard wall mount included.
- Front frame shall consist of a 0.125" tinted polycarbonate protective face.
- The polycarbonate shall contain UV inhibitors to protect the circuit board from the effects of ultraviolet light and prevent the premature aging of the polycarbonate face.
- The polycarbonate face shall have the following characteristics:
|Impact Resistance||Drop Test||0.5 lb No Break|
|Cold Bend||end Radius||100x material thickness|
|Sheer Weight||0.125"||0.78 lb/ft2|
|Thermal Expansion Rate||–||3.75 x 105 in/in ºF|
|Shading Coefficient||0.25" clear sheet ||1.02|
LED Circuit Boards
- LED circuit boards shall be manufactured using an FR-4 laminated fiberglass/epoxy printed circuit board with the front face printed with black UV cure ink or black paint.
- The failure of an LED string shall not cause the failure of any other LED string.
- The circular base of the discrete LEDs shall be soldered such that they are flush.
- Exposed traces, vias, and solder joints on the LED circuit board, with the exception of connector contacts and terminals, shall be protected from water and humidity by application of conformal coating.
- The conformal coating shall contain a UV brightener to aid in visual inspection.
- The presence of ambient radio signals, magnetic interference, and electromagnetic interference shall not impair the performance of the sign system. Interference includes power lines, transformers, and motors. The sign will not radiate electromagnetic signals that adversely affect any other electronic devices, including those located in vehicles passing underneath or near the sign and its’ controller.
- The Cabinet and sign components shall operate in the following temperature and humidity conditions:
- Operational temperature range: -30°F to +165°F
- Humidity range: 0% to 99% (non-condensing)
- Discrete LEDs
- The discrete LEDs shall be driven at a current level that is in accordance with their operating environment. Signs will use voltage pulse width modulation (PWM) to achieve the proper LED intensity level for ambient light conditions. The drive pulse shall be modulated at a frequency high enough to provide flicker-free operation.
- The LED drive circuit board shall contain a microcontroller regulation circuit that controls the PWM duty cycle.
- LED Specifications
|LED Type||Color (nm)||Min Brightness (mcd)|
|White||x= 0.31 y= 0.32||3,200|
- Regulated DC Power Supplies
- The LED Circuit board shall be powered with auto-ranging regulated switching power supply that converts the incoming AC electricity to DC, at a nominal voltage of 12VDC.
- Power supplied shall be UL recognized.
- Power supplies used to power the LED sign message and its controller board shall be identical and interchangeable.
- Power Supply Specifications:
- Operating input voltage range: 120-277 VAC or 12-24 VDC
- Typical power supply efficiency: 81%
- Minimum power factor rating: 0.93
- The power supply shall not be taxed beyond 65% of its rated maximum rated output.
- Power supply input circuit shall be fused.
- Automatic output shutdown and restart if the power supply experiences any of the following output faults: over-voltage, short circuit, or over-current.
Wiring and Power Distribution
- Internal Wiring
- Wiring for the sign components shall be installed in a neat and professional manner. Wiring shall not impede the removal of power supplies or other sign components.
- Wires shall not make contact with, nor bend around sharp metal edges. All wiring shall conform to the National Electric Code
- All internal wiring shall use drip loops.
- Earth Grounding
- Cabinet shall have one earth ground lug that is electrically bonded to the sign cabinet. All earth grounding shall conform to the National Electrical Code.