LED Ultra Sign Instruction Manual
00625-53-000
Page 9 of 13
Issue 4.1 19 January 2021
5
Wiring
The sign is powered by smooth regulated 24VDC. Normal one-way signs have one LED Driver circuit
board. Two-way signs and one-way signs with enhanced reliability have two LED Driver circuit
boards, each one operating half of the LEDs in the sign.
With the one-way enhanced reliability type it is possible to operate each driver from a separate
supply/circuit. In the event of loss of a supply, the sign can still illuminate at a lower brightness on
the other supply. For single-supply operation, it is necessary to wire the driver board supply
terminals in parallel. See Figure 6.
With two-way signs, either one driver or the other is powered to select the illumination colour and
message. Figure 8 shows a simple scheme to do this with a switch. Suitable controls are available
from Lasermet.
A three-way terminal block is provided on the driver board. Two terminals are used for the supply
connections. The third terminal may be used if desired for a remote dimming control voltage. The
connections are shown in Figure 4. Note that one-way signs have just one driver board.
It is preferable for the negative (0V) of the power supply to be connected to earth at the source. To
eliminate the potential for static electrical damage to the sign circuitry, the 0V terminal of each
driver board is connected to the casing of the sign through a 100Ω resistor. The sign contains no
hazardous voltages and it is not normally necessary to provide a dedicated earth connection for the
sign casing.
Where there are two driver boards and separate power sources are used for each driver board, the
negative wires of the two power sources should be connected together as shown in Figure 5.
A selector link is provided on the driver circuit board to choose the dimming method. If no dimming
function is required set the link to the ‘EXT/NONE’ position and make no connection to the DIM
terminal.
If using the internal sensor, set the link to ‘SENSOR’.
If using external control, set the link to ‘EXT/NONE’ and connect the external control voltage to the
DIM terminal.
The optional dimming control voltage is connected as shown in figure 7. The voltage should be in the
range 0 – 24V where increasing the voltage will increase the brightness. When using an external
dimming control voltage, the 0V of the control voltage must be connected to the 0V of the power
supply.
An external dimming control potentiometer may be used.
