Wintriss Shadow VI, User Manual

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Shadow VI User Manual 1107200
Introduction to Shadow VI Chapter 1 page 5
Safety Light Curtain
receiver transmitter light beams
Figure 1-3. Showing Light Beams with Shadow Light Curtain
Shadow's transmitter and receiver are not "matched sets". In other words, a Shadow VI
transmitter will work with any same-sized Shadow VI receiver. You mount the units on the
machinery on either side of the hazardous area.
Shadow can be described as an optoelectronic presence-sensing device. Presence-sensing
means the light curtain detects an object that penetrates its field and reacts to it by signaling a
press to stop when an intrusion occurs.
Optoelectronic means Shadow works using light and
electric current.
The transmitter's LEDs (light emitting diodes) emit a harmless, invisible, infrared light pulse
when an electrical pulse passes through them. These LEDs transmit light towards the
receiver. The receiver's
phototransistors detect each light pulse and produce an electrical
signal whenever the light pulse hits them. An invisible light barrier is formed by infrared
light beams sent from the transmitter to the receiver. Reacting to the loss of light, Shadow
sends a stop command to the press when there is an obstruction, such as when you put your
hand into the light field.
As the light curtain is operating, each transmitter LED pulses in succession from top to
bottom, in the form of a conical beam. The phototransistors in the receiver detect these light
pulses instantly and produce an electrical signal (turn on) when the light strikes them. Each
phototransistor detects the one pulse of light designated to it. It is only enabled at the instant
that the beam is anticipated. Shadow's electronics must "see" the phototransistor turn "on"
then "off" as the beam hits it and disappears. Each phototransistor must turn on, then off in
sequence, or Shadow will send a stop command to the machinery.