I want to make sure I am reading this correctly
If I am using the
Apollo 200 or 400
PSU, I count the
PSU and all connected Scrollers as a single device on the 32 device chain. Is that correct?
In the case of optically-isolated devices, like the
Apollo 200 and 400 units are - I'm making a reasonable leap here that Dave knows far, far more about that than I:
...as is the case with
Apollo's Smart
Power 200 and 400 supplies.
- You normally count each device downstream as a new
DMX run of up to 32 devices - within the constraints of the device's other parameters, namely cable run lengths and
power usage. In theory, at least, the
Apollo PSUs would be good for another 32 units on each run, disregarding
power usage; but you'd count the
PSU as a device on the originating run. Practically speaking, you'll normally reach the device limits on the "
power" side of the
PSU before the limits on the
DMX kick in.
In a situation like the setup you've got, using an optically-isolated
PSU means you have multiple, repeated
DMX sends for that
universe running on the 4-pin cables.
To make things slightly more complicated, most devices have a
passive DMX Thru, but can active
DMX output - that is, integral signal isolation within the device - which means they've taken the
DMX in, and are repeating it (thus restarting the count of devices).
DMX Splitters are an example of this, where they isolate the original
DMX run and repeat it to each of their outputs. Because isolation is typically an active process, (as in, no direct connections), it needs
power to operate properly - which is why it's common on many devices, even splitters, to leave throughput un-isolated. If the
power to such a device fails, since the connection is
passive, the
DMX passes through the
unit unhindered, leaving the remaining powered fixtures downstream still responsive. Naturally, the active outputs on the splitter would then no longer receive data.
And just for grins, if I have a Right Atm with a
scroller and
Iris is it one device or three?
The
Right Arm is 5-pin, with
passive throughput, so that's one
DMX device, the
power supply for the 4-pin output(s) to the
scroller and
Iris is another (although you may have a separate
PSU for each device, and it (they) may also be active or
passive output), so the total's two (and two), or three (and one, and one), or four, or four (and one), or five, depending. Easy, huh?
