Image Engineering LG4, User Manual

Page: 6 / 8

Image Engineering
Seite 6 von 8
3.3 Starting the system
The powerswitch (F) is located on the upper side of the control unit.
3.3.1 Power modes
The LG4 provides two intensity modes for the illumination
•
NORM : 32 kHz PWM, variable duty cycle
•
LOW : 32 kHz PWM, variable duty cycle approximately 1/10 of the NORM Mode power
output
Switch between the power modes by pushing and holding the rotary knob (B)
3.3.2 PWM (Pulse Width Modulation)
The LG4 uses pulse width modulation (PWM) to control illumination levels. The high frequency of 32
kHz allows a flicker-free image acquisition for most cameras. The constant current has the benefit of a
constant correlated color temperature.
LED intensity over time at 32 kHz pulse width modulation with 50% duty cycle
0 0,01 0,02 0,03 0,04 0,05 0,06 0,07 0,08 0,09 0,1
R
el
at
iv
e
In
ten
si
ty
Time [ms]
Puls Width Modulation with 32 kHz (simplified
representation)
Relative Intensity Period Time_on Time_off