Chronoskop CHR-9 Timegrapher
User manual
www.CHRONOSKOP.com
13
3.2. Optical Light Barrier measurement
Optical measurement is based on the principle of the light barrier. If the clock pendulum or
the minute hand interrupts or reflects the light beam of the transmitter diode, the receiver
diode of the time scale receives a pulse. Please note that the frequency of the infrared light
emitted by the diode is outside the visible range. Avoid strong extraneous light during the
measurement.
Light barrier measurement of the pendulum (internal light barrier)
Pendulum clocks can be measured with the optical light barrier. In order to measure the
clock with the built-in light barrier, the Timegrapher is to be placed with the outgoing infrared
LEDs and the supplied reflector toward the swinging pendulum, so that the pendulum
interrupts the invisible light beam (see picture bolow). If the invisible infrared beam of the
light barrier is interrupted, the Timegrapher registers an impulse. The reflector should be
aligned as possible directly opposite to the diodes, parallel to the rear wall of the housing. Do
not stick the reflector directly to the watch case. With a reflective pendulum you can even
work without the reflector.
Light barrier measurement of the pendulum (external light barrier)
When using the external light barrier place it so that the oscillating
pendulum passes through the light barrier between the two beveled
ends of the fiber optic columns.
Optical measurement of the minute hand (external Licht Barrier
Sensor)
The external light barrier also allows the measurement directly at the
minute hand. To do this, place the light barrier so that the pointer
passes through the light barrier during the hourly cycle.
The external light barrier is an optional accessory and can be ordered necessary.
