Mounting multiple DSCs - need ideas

[rm357]

If you want to do it without the passive hub...

I would remove the 120 ohm resistor from two of the DSCs and hook them up in parallel with the DSC with the 120 ohm resistor being the last one on the wire.

Why?
We are still using the rs-422 hardware layer that is used for DMX, just at a higher speed. RJ designed the system to be easy - every controller has a direct run to the hub. As a result, every controller has a terminating 120 ohm resistor. If you want to chain devices, you should really only have one terminating resistor at the end of each chain...

This is not a supported configuration because you can easily overload your wires, the traces on the hubs, etc. The fuse provides some protection, but it is really for catastrophic failures like shorts and hardware failures. If you draw 7 amps, it may take the fuse an hour to burn out while you silently cook the cat5 cable and traces on the hub... RJ built a safety into the SSCs by hard limiting them to 128 nodes. With the DSC, safety is up to you...

[tbone321]

IIRC, the fuse being used on the hubs is an ultra-high speed 5A fuse.  I would find it highly unlikely that it would support a current at 2A above it's rated value for more than a few micro-seconds and the traces and even the CAT5 cable could handle that for an extended period of time.

[rm357]

Look it up, it surprised me too.
At 200%, it blows in under a second, but the burn line on the graph doesn't even start until around 7 amps...

[tbone321]

Actually, if you look at that chart, it doesn't show anything below the 200% rating.  I guess that either they don't bother to test them below that point or they are too inconsistant to chart properly.  Either way,they appear to possibly take much longer than I expeted to blow at 2A over their rated value so it suprized me as well.