Engineers first addressed the challenge of remote lighting control back in the 1970s. It was during this period that the analog protocols 0-10V and 1-10V were developed. These protocols are still used today, including for controlling LED fixtures. Control data is transmitted via direct current sent to a special driver input.
The 0-10V Protocol
This protocol is defined by the American standard ANSI E1.3. Consequently, it is most common in the United States, though it is also frequently used in other countries.
In this protocol, 10 volts corresponds to 100% of the fixture's nominal light output. Zero volts corresponds to the fixture being completely powered down. By varying the voltage from 0 to 10 volts, the light output can be adjusted; 5 volts should correspond to 50% of the nominal light output.
A control panel operating on the 0-10V protocol is an active device, typically with its own power supply.
The 1-10V Protocol
This protocol is governed by the international standard IEC 60929. It is used worldwide, most popular in European countries, but is also found in the US.
In this protocol, 10 volts also corresponds to 100% of the nominal light output. However, the function of remotely powering down the fixture is not included in the protocol itself. The fixture must have a mechanical switch to cut the mains power. If remote on/off control is required, a contactor must be installed with a separate control line run to it. A control voltage of 1 volt corresponds to the minimum stable light output the fixture can provide. This parameter depends on the specific fixture, but in most cases, it is 10% of the nominal value for fluorescent lamps and 1% for LEDs.
A control panel for the 1-10V protocol is a passive device, powered by the driver. The simplest version is a potentiometer. The simplicity of the control panel's design is an advantage of this protocol. A 0-10V control panel can be connected to a driver supporting the 1-10V protocol if needed, but the reverse is not possible.
Modern Applications
The main drawback of analog protocols is signal degradation over long distances. However, analog lighting control equipment remains significantly cheaper than digital alternatives. This leads to the use of hybrid systems. For example, control signals within a large building might be transmitted digitally, but each room has a signal converter that outputs a 0-10V or 1-10V signal. Within the room, the analog signal is then distributed to the fixtures.
Another application is street lighting. The choice of a wireless control module for a streetlight depends on the specific location, so they are often designed to be removable. These wireless modules typically connect to the streetlight via a standardized NEMA 7-pin connector. Control signals from the wireless module to the fixtures are most often sent using the 0-10V protocol, as it is the cheapest option among standardized interfaces (although the NEMA 7-pin connector can also transmit digital data if necessary). In this case, the signal experiences minimal degradation because it is transmitted over a very short distance.
