Dolby CP 650

[Jim Cassedy]

The CP650 on the change-over system at my regular venue, and also at a
screening room I work at is wired so that the LCD display shows when one
or both motors are running, and then the little "P1 /P2" lights under the
volume indicator light to show which projector source is active.

Both the Projector One and Proector Two motors were turned on when I took this
picture, like they would be while running down the leader just before a change-over.
CP650_LCD.jpg


Sound source was Projector Film-Tech Forums here
CP650_Vol.jpg
Because I can easily see the CP-650 and the "P-Indicator",
from across the room, I always glance over to it when I'm
stating a film show to confirm which projector source I'm
switched to. ( Since all the pre-show stuff & trailers are
almost always from DCP, I also glance over at the TRINNOV
display just above the CP-650 to make sure it's taken the
automation cue to switch over to the film sound mode)

[Marco Giustini]

So what is the advantage/disadvantage of having both Motor sensor running on a changeover system?

[Tj Hopland]

I think Jim is just demonstrating that both M1 and 2 can be on at the same time so perhaps in this case where it has been explained that he never plans to make an actual real changeover that a possible path would be to install jumpers for both M1 and M2. We are kinda thinking that could maybe work for SRD unless there is some sort if timeout if it doesn't see the next reel? If that works then he could just use any old switch like a light switch on pin 3 and flip that to ON for P2, OFF for P1.

Thinking about it now has he even said if he is using SRD? If yes is there a reader on both projectors? If its not on both then its easy just install the jumper for which ever projector has the SRD reader on it. If there are no SRD readers currently in use then its even easier, it doesn't matter no jumpers or switches needed for the M1 M2 stuff till some SRD readers are installed. Still need a switch for the P's but as I said a simple light switch to pin 3 would do that.

If you (or others) are going the conventional relay route look up what are known as RIB relays. RIB stands for Relay In Box and are made by a company called Functional Devices. Tons of options for different applications that can make for a much better installation compared to having to get relays and sockets and then mount all that in a box especially when its just one relay per location. There are some really common ones that lots of people stock so are really easy to get. Other models will likely have to come from a dealer like an electrical supply house.

[Neal Scanlan]

Hello
So in conclusion I have one switch, Pin 1 and 5 for P1 and Pins 5 and 9 for P2. I connected another switch with a separate ground pin 5 to pin 3 and everything works perfectly with both readers on the two projectors. It does mean I need to be observant on startup but as I am under no ‘show pressure’ I’m happy with this solution.
Thank you all for helping me through this.

[Marco Giustini]

amazing! Consider the idea of wiring the P line to the dowser - via a relay.