What Is Daisy Chaining and How Many Stage Lights Can You Link?

On a DMX data line, you can daisy chain up to 32 fixtures per run before you need a splitter, as long as their channels fit in one 512-channel universe. On power, the limit is the lower of two numbers: the maximum the fixture's power-out socket is rated for (printed on the fixture or in the manual) and what the circuit can carry at about 80% of its breaker rating.

What daisy chaining means on a stage rig

Daisy chaining means linking fixtures one after another instead of running a separate cable from the source to each one. Stage fixtures usually have two independent chains, and each has its own limit:

• DMX chain: the controller feeds DMX IN on the first fixture, that fixture's DMX OUT feeds DMX IN on the next, and so on to the last fixture, which gets a 120 Ω terminator in its DMX OUT.
• Power chain: many stage fixtures have a power-out socket next to the power inlet. One feed from the wall powers the first fixture, and short link cables carry power on to the next ones.

The two chains do not have to follow the same order. You can run DMX left to right across the truss and split power into two shorter chains fed from different circuits.

In electrical terms, a power daisy chain is wired in parallel, not in series. Every fixture gets full mains voltage, but the current adds up as it travels back toward the wall. The first link cable and the first fixture's internal through-wiring carry the current of every fixture after it. That is why the power-out socket has a rating, and why the same rule applies to household plug-in string lights: the "connect up to X sets" line on the tag is the limit, no matter how many sockets you can physically plug together.

How many fixtures on one DMX chain

Three limits apply to a DMX run. Whichever you hit first is your real limit.

The 32-device rule

DMX512 uses RS-485 signaling, and a standard driver is rated to feed 32 receivers. Each fixture's DMX input counts as one. So does a wireless DMX receiver plugged into the line, or a splitter input. Past 32, the signal edges get soft and fixtures near the end start to twitch, flicker, or ignore commands.

Some newer fixtures present a lighter load and the line may work past 32, but plan on 32 anyway. Budget fixtures rarely state their load, and a rig that works on the bench can fail in a venue with long cable runs and dimmers nearby.

The channel budget

Every fixture takes a block of channels starting at its DMX address. Add up the channel modes you plan to use:

• 12 PAR lights in an 8-channel mode = 96 channels
• 4 moving heads in a 16-channel mode = 64 channels
• Total = 160 channels, which fits a 192-channel controller and leaves most of a 512-channel universe free

The two limits can cross over. Thirty-two moving heads at 16 channels each use exactly 512 channels, so one universe and one run are both full at the same time. Forty small PARs in a 4-channel mode use only 160 channels, but 40 devices is already over the per-run limit, so you need a splitter even though the universe has room.

Fixtures set to the same address do not need extra channels. Four PARs all addressed to channel 1 will mirror each other and use one block of channels, but they still count as four devices on the run.

Cable, termination, and splitting

• Use 120 Ω DMX cable. Microphone cable has the same XLR plugs but the wrong impedance, and errors show up on longer runs.
• Put a 120 Ω terminator in the DMX OUT of the last fixture on every run, including each output of a splitter.
• Do not split a DMX line with a passive Y cable. Use an opto-isolated splitter, which also stops a fault on one run from taking down the others.
• Check what happens to the chain when one fixture is unplugged from mains. On some fixtures the DMX through-port only works while the fixture is powered, so switching off one light in the middle can kill everything after it.

A practical layout for a small rig is one splitter near the controller with a run for each position: front truss, back truss, and floor. A fault on one position then leaves the others running, and a dead section points straight to the cable or fixture where it starts.

How many fixtures on one power chain

Power chaining has two separate ceilings, and you work out both.

Ceiling 1: the fixture's power-out rating

Look for a current rating printed next to the power-out socket, or a line in the manual giving the maximum number of units you can link at a given voltage. That figure protects the socket and the fixture's internal wiring, which carry the current of every fixture downstream. If you cannot find it, treat the fixture as having no safe power-out capacity and feed it separately until you confirm the rating with the manufacturer.

Voltage changes the count. The same fixture draws roughly twice the current at 120 V as it does at 230 V, so a manual that allows a certain number of linked units at 230 V will usually allow about half as many at 120 V. Japan runs at 100 V, so current per fixture is higher again.

Ceiling 2: the circuit

Current in amps equals watts divided by volts. For planning, keep continuous loads to about 80% of the breaker rating. In the US this is how the NEC treats continuous loads; elsewhere it is a common planning margin, and local rules decide what is required.

Use the input power from the fixture's rating label or manual. The wattage in a product name may describe the LEDs rather than what the fixture draws from the wall, and the label figure is the one that matters for breakers.

Worked example

Say the rig is 8 × ZQ01061 145W PAR light and 4 × ZQ02042 230W BEAM, and the label figures match those wattages:

• PARs: 8 × 145 W = 1,160 W
• Beams: 4 × 230 W = 920 W
• Total: 2,080 W

At 120 V that is 2,080 ÷ 120 = 17.3 A. It is over the 12 A budget of a 15 A circuit and over the 16 A budget of a 20 A circuit, so split it: the 8 PARs on one circuit (9.7 A) and the 4 beams on another (7.7 A).

At 230 V the same rig draws 2,080 ÷ 230 = 9.0 A. That fits a 16 A circuit (12.8 A budget) and a UK 13 A plug (10.4 A budget), but not an Australian 10 A outlet (8 A budget). There you would split it the same way: PARs at 5.0 A on one outlet and beams at 4.0 A on another.

Then check ceiling 1. If the PAR's manual allows fewer than 8 linked units at your voltage, start a second chain from the same circuit with its own feed cable.

Power-chain habits that prevent trips

• Moving heads draw extra current while they start up and home. Power a large chain in groups, a few seconds apart, rather than all at once.
• Use link cables rated for the full current of the chain. The first link carries the most.
• Do not extend a chain by plugging power strips into each other. If you run out of reach, run a new feed from a properly rated outlet.
• Keep power and DMX cables apart where you can, and cross them at right angles where you cannot.
• If the same breaker trips twice, stop and reduce the load. Resetting it again does not fix an overload.
• Outdoors or anywhere damp, use GFCI (US) or RCD (UK, EU, AU) protection, and get a licensed electrician for anything beyond plugging into existing outlets.

Planning a chain on paper

1. List every fixture with its channel mode, label wattage, and position.
2. Group fixtures into DMX runs of no more than 32, ideally one run per position.
3. Assign addresses so channel blocks do not overlap, and confirm the total fits 512 per universe.
4. Group fixtures into power chains that respect each fixture's power-out rating.
5. Add up watts per circuit, convert to amps at your local voltage, and keep each circuit within 80% of its breaker rating.
6. Mark the last fixture on each DMX run for a terminator.

FAQ

Can I mix fixtures from different brands on one DMX chain?

Yes. DMX512 is a shared standard, so brand does not matter as long as each fixture is in DMX mode, has the right address, and the run stays within 32 devices. Problems usually come from overlapping addresses or a fixture left in auto or sound mode.

Does a wireless DMX receiver count toward the 32?

It counts as one device on the wired line it plugs into. On its output side it starts a new run, and the fixtures it feeds count toward that run's own 32.

How many moving heads can I run on one household outlet?

Divide the outlet's 80% budget by each head's label wattage. On a 15 A, 120 V circuit (1,440 W) that is six 230 W heads; on a 16 A, 230 V circuit (2,944 W) it is twelve. Check the power-out rating as well, and remember that other things on the same circuit use part of the budget.

Why do the last few lights on my chain flicker?

Check the end of the line first: a missing terminator, a mic cable in the run, or one worn connector. If the run is over 32 devices or very long, split it. If the flicker follows one fixture when you swap positions, that fixture's DMX port needs service.