As part of the electrical work I was doing over the last few weeks I was working on the main switch component for the 12V supply. The main reason for such a switch component is the goal to minimise power consumption. Each control component like a valve control, dmx control unit, slide-out controller and any other component use power even on standby. Audio PC, video PC, cameras, NVR and other 12V units add significantly to an idle current which could amount to 3-5 Amp, which is almost as much as a small 12V fridge would use when running continuously, which it normally would not.

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I use 8 latching relays with nominal current capacity of up to 100 A each. The connections at the top of the block are the wires to the relay coils as well as a common connection to each coil to engage and disengage all relays with a manual switch when the central system is not available. I used a copper bar to connect the supply contacts. The small wires at the other contacts are used as feedback lines to the connected Arduino to monitor the operation of the relays.

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This is the control box for the switch block. I use a small micro processor board called PoKeys57e. It is connected to the central system by Ethernet. I am not using the can bus for this component since the whole can bus can be switched off but at least on Ethernet switch and the central system remains running. This little board has up to 52 signal connections for different purposes. I only use a small part of it’s capabilities in this ¬†application. The 16 relays for each of the signal connections to a coil of the latching relays are driven by the PoKeys57e “extended bus” and commands over the Ethernet.

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I use 2 cables to connect to the switch block, a 25 pin D-Sub for the 16+1 signals for the coils + ground and a 9 pin D-Sub connector for the 8 feedback lines.  I also implemented a page on my central app to test and manually control the switches. Later the switching of these relays will be part of more complex control sequences.

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The image below shows the final position for the relays and the control box inside the TV unit.

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