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µSD card
Slot for µSD cards.
WLAN
WLAN/Bluetooth interface, including two WLAN antenna connectors.
Trigger input
Any of the available optocoupler inputs or TTL inputs can be used for triggering. The input line mapping
on the camera connectors is described in Section “
Connector and cable description
”.
The characteristics and default behavior of these interfaces are described below in Section “
Optocoupler
interface
” and Section “
TTL I/O's
”. Those sections also provide examples how to connect the inputs.
Optocoupler interface
Optically isolated inputs and outputs.
Optocoupler basics
An optocoupler is a device using optical path to transfer an electronic signal between two circuits. It
basically consists of a photodiode converting the input signal to light and a phototransistor converting
the light again to electronic signal.
Diagram of basic optocoupler function
The optocoupler is useful in situations where one part of the circuit needs to be galvanically isolated
from the other part to prevent damage or unwanted interference. It is used to prevent ground loops or
to block voltage spikes.
For effective use of the optocoupler it is important to control it using an independent power supply.
When the external circuit is galvanically connected to the camera (eg. when reusing the camera's power
to control the optocoupler), the optocoupler's protective function is eliminated.
Optocoupler inputs
The CORSIGHT camera is equipped with four optically isolated input lines. One input optocoupler is fully
independent, the other three are connected with a common cathode (Section “
I/O connector
”) due to
limited number of pins on the I/O connector.
The optocoupler input's logical state is understood as logical
0
if no current is flowing through the
optocoupler diode, logical
1
if current is flowing through the diode.
