tally control device

[3kids]

Can anyone draw me diagram for tally control for a video switcher. The tally output is a 15 pin D-sub connector.
Pins 1 through 8 are correspondents to each input of the switcher. Ex: camera 1 triggers the out of pin 1 of the tally output. It uses an open collector circuit for each pin. these contact closures need to trigger a led or lamp remotely at the cameras location that way the talent know what camera is live. Im guessing the wiring length to each camera would probably be around 150 feet. I forgot to mention that maximun curent draw would be 50ma/max voltage 24 volt dc

 

[richs]

Hi-

Tally lights vary from camera brand to camera brand. I suggest that you obtain a copy of the manual for the camera before doing any wiring. Also a reference to the video switcher will most likely point you in the right direction.

"IN GENERAL" most tally lights are low voltage lamps. Sourcing one side with power (through a fuse) and the other to each of the tally light inputs through the camera cable or to the camera control unit prior to the switcher. The cable in this case is not just the multicoax cables, but the cable including the CCU and PL wires.

I would strongly suggest that the station engineer be contacted prior to attempting to do this. If this is a remote operation, a call to the video switcher folks should point you to the manual and hence the circuit used for the tally lights.

Best of luck.

Cheers,

Rich S.

 

[MacGyverS2000]

A very similar question was raised a few months back... do a search, assuming it wasn't red-flagged for whatever reason.


Dan - Owner

http://www.Hi-TecDesigns.com

 

[itsmoked]

I already looked Dan and I couldn't find it.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[3kids]

i apologize for not explaing my past, I have been an electronic technician for 20plus years, and have done small design work. i basically do systems integration and A/V installs. I have been out of it for so long, i just need to quicklyrefreshen myself,

Again , the switcher basically uses an open collector circuit at the output, as the soon as the switcher keys in an input bus it would trigger contact closure at the tally
port for that input. I feel that it needs a relay controlled circuit with a supply voltage hanging off it( supplied by the external power source)once relay is closed the power would therfore light up the lamp, My fear is that the cable length may throw off the supply voltage.the switcher specify that no more than 50 ma may be drawn from it.