With release 38rcX NAMF reports more info about HECA. SHT31 used in HECA has alarm feature. It tracks RH and temperature and when is out of given presets ALARM pin on SHT31 is enabled. We use that to control heating element when air is too cold or too humid.
On /status page HECA reports duty cycle. This is how long alert was enabled due to humidity (DutyCycleRH) or
temperature (DutyCycleTemp). DutyCycle is total time when alarm was active, no matter what condition
has triggered it. DC is in %, so 50% means that alarm (and heater) was on during half time since last sending data.
Duty Cycle shown on /status page, and on LCD is from current cycle (so, it will be changing if heater is enabled).
Values presented in /data.json are from previous cycle (sent to APIs).