P-DMX/Distributor

Introduction


The P-DMX distributor is a central hub, where DC power and DMX are combined into the same CAT5 cables for distribution to remote display elements.

One Channel


Here's a block diagram for one channel of the P-DMX distributor.



The incoming power (24-48 Volts DC) goes to each output socket (RJ45) via a small (2 Amp) fuse. This protects the output cabling in the case of a short circuit. It also ensures that an overload on one output does not affect the remaining outputs. If the outputs were not individually fused, a short on one output cable could cause the maximum power supply current (possibly > 20 Amps) to flow in the shorted output cable. The result could be a molten mess of cable and RJ45 sockets!

You'll see that there is one DMX input for each pair of P-DMX outputs. The RJ45 pin-out is per the official ESTA recommendation. The DMX signal is terminated and buffered before being regenerated to send to it's respective pair of outputs. Each output must be terminated at the end of the line, just like any other DMX system. There is no need however to terminate an unused RJ45 output on the distributor.

The RJ45 pin-out of each output is also per the ESTA recommendation, with the addition of power (24-48 Volts DC) added to the centre pair.

The Whole Unit


The block diagram below shows how the 4 individual channels combine into one overall distributor. There is a separate input for each 2 channels. This gives a maximum current draw of 8 Amps per 2 channels (4 RJ45 outputs).



PCB jumpers are provided so that any channel output pair can select either it's own DMX input, or the preceding one. This allows the user to use just one DMX to feed all channel outputs if desired. It alternative allows for grouping of inputs. eg. Input 1 to channel 1 + 2 outputs and input 3 to channel 3 + 4 outputs.

Lastly, there is a power LED for each channel output as well as an activity LED for each DMX input.

Summary


  • 4x DMX inputs (RJ45 sockets)
  • 8x P-DMX outputs (RJ45 sockets)
  • 2x DC inputs (8 Amps max each)
  • User replaceable output fuses (2 Amp mini blade)
  • Power available LEDs for each channel output
  • User replaceable RS485 (DMX) chips
  • Data LED for each DMX input



[category]Category:DMX[/category]
[category]Category:P-DMX[/category]

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