ELK-PS212S, M1DBH, how to split power

[Linwood]

Have a PS212S that I just got to power an Uplink.

I am using a M1DBH to connect everything else on the data bus (except one keypad just in case and since it was already wired with 4 wire).

In reading about the PS212S, if you daisy chain data bus devices from it with the ribbon cable, then it powers each of those boards instead of the M1G.

If you wire everything (including it) to the M1DBH, that's clearly not so since the hot is isolated on the connection.

But if I wanted to shift some load to the PS212S and off the M1G, can I do this?

- M1G Data Negative to M1DBH data bus negative AND ALSO PS212S Data bus Negative to M1DBG Data bus negative

- PS212S Data bus + to M1DBH data bus + (so the M1DBH has no + attachment to the M1G at all)

- A and B Data bus to M1G as usual

- A and B and negative in the RJ45 to the PS212 from the M1DBH as usual (+ is already isolated).

And if I do that, I think everything on the M1DBH is powered by the PS212, and not by the M1G. Right?

Not sure I want to -- any problem then takes half my zones, RF, one keypad, etc.

The alternative is I have to pull devices off the M1DBH, or (uck!) run separate power cables to them paralleling the RJ45.

Do I have all that right?

 

[DotNetDog]

I'll have to look at my system tonight when I get home so that I can draw it out exactly, but I did essentiall what you are trying to do (I think). However, my wiring is a bit different that what you're proposing. Unfortunately, I can't quite remember... I'll post a drawing of my wiring this evening.

I have 6 input expansions, 2 DBHs, and much more. So I use the P212S and a PD9HC to deliver power to things. I have two RS485 branches off the M1G. The first branch uses power straight from the M1G so I plug in devices that use very little power. I do have 1 keypad in this branch.

The second 485 branch starts with a DBH and is powered by the P212S. I plug in 3 more keypads here. My glass breaks all get their power from the PD9HC, too.

Anyway, I'll draw it up this evening and post it here.

 

[Linwood]

The second 485 branch starts with a DBH and is powered by the P212S. I plug in 3 more keypads here. My glass breaks all get their power from the PD9HC, too.

Doing that is pretty straightforward, e.g. having 2 DBH, one powered by the P212S and one by the M1G itself. at least I think so. I only have one, which is why it seems either complex, or all-or-nothing. Let me know what you think when you see it.

 

[Del91574]

How many devices you have off the 485 bus would determine what you're dumping off the M1 to loadshed, however since the Uplink draws upwards of 2A for a brief transmission period, I would strongly recommend limiting what you attempt to shift to the 212S if you already have ample power on the M1.

Your basic understanding of how the 212S would isolate the + connection from either a DBH or the panel itself would be accurate. The easiest way, if I'm reading correctly of what you're trying to do, would be to run the 212S into the DBH towards the end of the 485 bus and make an appropriate jumper for the 485 that dumps power on the dead terminal and one that is grabbing power from the 212S. As I said, I'd be very wary about what else you land on the 212 besides the Uplink, and honestly, for the purpose of loadshedding, I would recommend putting the Uplink on it's own power supply, either a "dumb" unit or it's own supply and if you still need to loadshed, look into another 212S.

 

[DotNetDog]

Linwood, you're right... My wiring is actually simple. DELInstallations seems to be pretty knowledgable on this still and I'm a mere newbie. It sounds like you are on the right track.