Schematic Help two power supply wires?

Below I have attached the schematic I am having trouble with.

Not sure why it list two power supply wires for single phase use? And what the proper wiring method would be.

Thanks in advance for any help!

Terminals 7 and 9 are the normal +/- DC power supply. The lights themselves are switched negative. Terminal 8 is a convenience DC negative that presumably goes to high impedance on a preset pace to produce synchronized flashing lamps. I wouldn’t use terminal 8 with a PLC.

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@pturmel For 120 does it matter if i put the single hot to the gray or the black?

Placement of fuse in wiring diagram and black wire color both suggest 120 V AC hot goes on black with neutral on gray.

@witman neutral is Yellow?

120 V AC neutral line is gray in this diagram (120 V AC on black, and AC neutral on gray):

I expect the AC version has an internal DC power supply that outputs power continuously to the LEDs. As @pturmel notes, switching the negative to closed to complete each LED’s circuit back to yellow (0 V DC / DC common) would turn the LEDs on.

@witman Those are both “power supply wires” for when using 240 and needing two hots. You cut it off, but right above the gray it says common line Yellow.

If it has a clearly marked common why would I assume something labeled power supply which is presumably a hot, be a common?

You only use the left wiring diagram, or right wiring diagram, depending on which part number you have. Left diagram uses DC supply. Right diagram uses AC supply. In right diagram, I expect yellow is DC common for internal power supply to complete the circuit through LEDs. I cut off above grey wire as input power supply is just grey and black for 120 V AC supply–or 100-240 V AC supply per diagram. It’s a wide-input supply and works with anything from 100 V AC to 240 V AC between grey and black.

This I know. That being said the DC diagram does not show the black which is AC. So why would the AC show something extra which is DC? More than likely not, because it is AC.

It seems pretty clear to me that the AC model simply has a DC power supply whose negative is brought out to the yellow terminal. AC neutral ≠ DC common.


The Yellow completes LED circuit to internal DC power supply (which is powered by your 100-240 V AC connection between grey and black). You’ll notice diagram for AC does not show Yellow connected to power supply.

@witman so the lights get hooked up to a DC common to work?

Also why is the yellow DC common in AC circuit but DC + in DC circuit?

Sorry I don’t why this is so confusing to me. lol.

@pturmel Why is it listed as DC + in the DC circuit if its a negative being brought out in the AC?

No worries. Yes. they use gray for DC common on the DC model, and yellow for DC common on AC model. This is just their wire color choices for the two models; ignore DC diagram for AC model.

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Because they can. Something has to get a new wire color. May as well be that.

@pturmel and @witman so just to verify.

Do I have to hook up the yellow DC common or is not needed seeing a light will make that connection?

And lights get hooked up to a DC common correct?

Idk what wrong with me today lol but I think I’m coming around.

AC means gray and black get two hots or a hot and a neutral.

The for the lights to work let’s say I throw up a terminal block > plug in my yellow. Then whatever light I plug into the yellow terminal bridged block will work. At which point I just use a relay to break the circuit.

Did I get that right? Lol

Because the lights are presumably 24vdc all the AC does is power an internal power supply stepping it down. While the DC gets external power supply voltage.

Weird and confusing but I guess I get it now. I guess it’s one of those I will cause I can kind of things .

I think the key here is that a buyer thinking the AC model can use AC for the individual lights will be quite disappointed. For both models, a PLC would need to switch the lights with an NPN open-collector output card.

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That sounds about right, except the LEDs will not make the connection. You’ll switch negative/common externally to turn LEDs on/off. The external contacts (PLC potential free relay output, or just relays, though I hate adding those to a system) would connect them back to Yellow wire.

Or you could probably use a sinking output PLC card to switch these (rather than relays) by connecting Yellow wire to the same ground potential as the sinking output PLC cards. You don’t want a floating power supply with unknown voltage to ground connecting back to a PLC. These things work better when we don’t let the smoke out.

EDIT: @pturmel beat me to it.

Yeah it was a McMaster buy so I didn’t see the diagram. And it added to confusion which may have not been there otherwise. Is for a AC cabinet. No outs on the plc avail. But since I get the yellow common Internally. I’m just gonna throw some slim AC relays in there to switch the led common to the yellow on and off.

Thanks , I really appreciate you guys dealing with me today lol

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