Production Switchers

I am planning on using the tally outputs to drive LEDs and wanted to make sure I have the output rating right on the tallies first.

In this manual: http://community.rossvideo.com/wp-content/uploads/Carbonite_Setup-Manual4802DR-120-10.0-E.pdf

They are listed as this:

Specification Value

Input Voltage 24VAC(rms)/40VDC

Maximum Current 120mA

Impedance

Daniel,

Tallies are open collector devices. They accept a voltage and essentially close the circuit when told to "activate". They do not supply voltage. Camera CCUs and even old school monitors have a two pin connection that needs to be made to the switcher "tally and common" that allow the switcher to basically turn on the "light switch" for them when they are active.

This means that unless your circuit you are designing has the voltage supply in the line and then uses the switcher as the "light switch" then you will not be able to drive the LEDs.

The GPOs can provide Voltage but you might be better off depending on what your trying to achieve to design a power source into your circuit that uses a momentary switch (for debug) that simulates the switcher Tally. Then once you have that working you can remove the momentary and connect those two connections to the switcher.

Les

#Carbonite

Hi Daniel,

Further to what Les said, I've had success with supplying 3V, through appropriate pull-up resistors, to the tally pins (from an Arduino Due), so it doesn't need to be as high as 40V to work. You supply the voltage, the Carbonite makes the connection to common (ground) to complete the circuit.

If I remember correctly, GPO supplies 5V (I have it connected directly to an input pin on another Arduino that's running at 5V).

James.

#Carbonite