Dimming & control

How far can a 0-10 V signal cable run

0-10 V distance is limited by summed sink current against cable resistance, not a voltage threshold. Includes a units x cable size x length table and a two-point test.

Last updated：2026-10-31

"0-10 V runs 100 metres" is missing three variables: how many drivers share the loop, what cable size, and how much drop you allow. 0-10 V is absolute voltage coding, so every volt lost on the cable becomes a brightness error directly. The signal loop is more sensitive to voltage drop than the power loop, not less.

The one-sentence rule: work out the drop first, then talk about distance

dU = N x I_sink x 2 x L x R'

N       number of drivers on the same control loop
I_sink  signal sink current per driver (A)
2       both ways, out and back
L       one-way length (km)
R'      one-way cable resistance (ohm/km)

Pass condition: dU no more than 0.5 V. The far end must still see at least 9.5 V for the driver to read it as a genuine 100%.

Usual values for the three variables

Sink current: on a 0-10 V interface the voltage source sits in the driver and the controller pulls the voltage down by sinking current. Published technical material commonly quotes 0.1-2 mA typical per device with a 10 mA per channel maximum (the interface characteristics are defined in IEC 60929 Annex E and the later IEC 62386 series; follow the manufacturer datasheet). Size the length on 2 mA per unit, not 0.1 mA.

Cable resistance (copper at 20 degrees C, one way):

Allowable drop: 0.5 V on a 10 V span is 5%. That looks like the familiar 5% power-side limit, but the consequence is different. On the power side 5% costs efficiency and a little output, and a constant-current driver compensates within its input range. On the signal side 5% of drop is 5% of setpoint error, shared by every driver on the loop, and the client will see it immediately.

Maximum length table (dU no more than 0.5 V, 2 mA per unit)

Why long runs jitter at the bottom: the signal-to-noise ratio is amplified twentyfold

The interference picked up on a given long cable is fixed. Assume 50 mV:

• at 10 V full scale, 50 mV is 0.5% - invisible
• at the 0.5 V low end, 50 mV is 10% - visible as brightness jitter or hunting

The same interference is twenty times more significant at the bottom of the range. That is why "fine at full output, jittery at minimum" is almost always a cable length and interference question, not a driver quality question.

Two measurements that tell you whether it is length or source loading

This step saves a lot of pointless recabling.

Step 1 - measure at the near end

Measure at the signal terminals of the controller or the first driver. If the near end is only 9.6 V or less, the source cannot carry the load - the parallel unit count exceeds what the 10 V source can feed. Thicker cable will do nothing here. The fix is splitting the loop into two halves, or adding a signal amplifier.

Step 2 - measure at the far end

Measure at the terminals of the furthest driver. If the near end reads 10.0 V and the far end 9.3 V, all of the 0.7 V is on the cable. That is a genuine voltage drop problem and the table above fixes it with cable size or distance.

Four ways out when the table says you are over length

1. Increase cable size: 0.75 to 1.5 mm2 doubles the allowable length for modest extra cost, and it is the most direct answer
2. Split the control loop: one loop of 50 becomes two of 25. Allowable length doubles and the source loading problem disappears at the same time
3. Add a signal amplifier or repeater: standard practice beyond roughly 300 m with many units. Check the amplifier's own output drive capability as well
4. Move to DALI: a digital signal is insensitive to drop and interference, so long runs and high unit counts stop being a problem at the root. The cost is higher demands on cabling and commissioning

Installation and acceptance checklist

1. Take the sink current per unit from the datasheet; if it is not published, use 2 mA per unit
2. Count the drivers on the same control loop - do not mix dimming zones into one number
3. Apply dU = N x I_sink x 2 x L x R' and require dU no more than 0.5 V
4. Measure near end and far end and apply the two tests above
5. At full output the far end must read 9.5 V or more; at the 1 V setting watch for ten seconds with no visible jitter
6. If length or count is over the table, pick one of the four routes above rather than just going one size thicker and hoping

Workmanship minimums: use screened twisted pair for the signal (purple positive, grey negative, polarity consistent throughout), keep it separated from 230/400 V power cables and cross at 90 degrees where separation is impossible, and treat the signal loop to SELV / Class 2 isolation requirements - follow local rules and the authority having jurisdiction for the detail.

Units in the H series with 0-10 V terminals, such as H01, H07 and H19, all go through the same calculation. On projects with high unit counts, split the loops at drawing stage rather than discovering the problem at commissioning. For wiring and application fit across all six dimming methods see the dimming comparison table; for power-side drop and cable sizing see the 12 V/24 V voltage drop and cable size table, and use the LED driver sizing calculator for circuit current and power checks.

© 2026 YFX. Figures are for selection purposes. Always follow the datasheet and local wiring regulations for final installation.