Brad Stevenson of Douglas Lighting Controls was the guest speaker for a San Diego IES meeting. Brad provided an excellent overview of lighting controls systems and mentioned some interesting pros & cons of digital vs. analog switches, as they pertain to lighting controls systems.
I asked Brad to provide a short write-up of these elements to publish here. See below for Brad’s synopsis of digital switches.
While the use of digital switches is ideal for many lighting control applications care must be taken with the digital switching layout. All digital systems communicate over a dataline but all datalines are not equal. Some datalines require a start-point and an end-point and do not allow t-tapping or splicing. While these datalines are simple to draw (panel-to-switch-to-switch-to-panel-to-sensor, etc) they are not simple to maintain. Removal of a single switch will interrupt the dataline and will therefore disrupt the entire lighting control network. This can cause disastrous results as removing a switch from a classroom will interrupt communications in an entire school.
When using digital switches the best practice is to run a trunk dataline, in conduit, between each of the lighting control panels. Then run a separate branch dataline connecting the switches in each tenant space or classroom block. This simple design ensures all panels remain connected to each other and further ensures that the removal of a switch within a tenant space cannot affect the lighting controls in other tenant spaces.
These days, most people assume the latest technology has to be the best and therefore, a no-brainer when it comes specification on a project. As Brad has pointed out, there are still occasions where analog based systems may perform better than their digital counterparts.
Thanks, Brad.