Raphayo 43 posts since
Jun 12, 2008
1.
Re: Controlling a dry contact input device (Cam Switcher) with logic box outputs Jan 31, 2010 7:00 PM
Hi RJ,
The text below have been took from the Nexia Manual on the Biamp Website.
The Logic Box provides up to 20 logic outputs.
Logic outputs can be used to control relays and
indicators or to drive logic inputs of other devices. The Logic Box logic outputs are 'open collector' with
an internal pull-up. Each logic output is an NPN transistor with the collector being the output and the
emitter being ground (see diagram below). When a logic output is turned on, the transistor provides a
path for DC current to flow, lowering the output voltage to below 0.8V. When a logic output is turned
off, the internal pull-up resistor raises the output voltage to near 5V, depending on the output current.
To activate external relays or indicators, an external power supply must be used (see diagram below).
The logic output transistors are rated up to a maximum of 40 VDC and 500 mA per output (24 volt
relay coils maximum). However, +12 Volts DC is sufficient power for most applications. When using
the logic outputs to control relays, protection diodes must be used to suppress high voltage transients
that are generated when the relays turn off (see diagram below).
Just connect the signal and ground to the camera.
Regards,
RaphaYo
