One of the most persuasive words in marketing has got to be “free,” despite the fact that we generally know that nothing in life is truly free, especially when it comes to LED drivers. Dimming functionality in drivers, implemented based on 0-10V controls, is sometimes touted as free, but in reality nearly every technology decision has a cost associated with it. Read along to learn about the issues with 0-10V LED drivers that can lead you to optimal selection and understand how more-robust digitally-addressable drivers may ultimately prove more economical in an actual solid-state lighting (SSL) project.
The adage that nothing truly comes for free is certainly true for 0-10V LED drivers. Many 0-10V LED fixture manufacturers offer dimming drivers as a no-cost upgrade versus what we will call switching drivers, or drivers that can simply be turned on or off via a relay or other control. The free 0-10V upgrade is intended to help manufacturers sell their fixtures to building owners, contractors, and specifiers.
Related article: FOCUS ON: Robust LED drivers are critical to enabling quality solid-state lighting
At first glance, when you are deciding between specifying an analog 0-10V dimming driver and a digitally-connected and -addressable dimming driver, it seems like an easy choice. With 0-10V drivers you get all of the benefits of LED dimming at no additional cost; however, it is not typically that simple. It is important to consider a variety of factors such as whether the dimming performance will meet your requirements, additional costs associated with meeting new codes and standards, and technologies that may not stand the test of time.
Overview of dimming LED drivers
Let’s first step back and consider the dimming-driver technology options we are discussing here. A 0-10V control is an analog control type and the interface to the LED driver consists of two pairs of wires:
• A 120/240/277V line-voltage switch (Class 1 wiring)
• Low-voltage dimming control (Class 2 wiring)
Line voltage to the LED driver is switched in order to turn the driver on and off. A low-voltage control element such as a wall switch, meanwhile, delivers a control input to the driver by varying the voltage between 1 VDC (minimum light) and 10 VDC (maximum light). The driver associates this control input level to a particular dimmed level of the LED light engine. Since the control signal is a small analog voltage, long wire runs can produce a drop in the signal level, which results in varying light levels from different drivers managed by the same control device.