HVAC (Heating, Ventilation, and Air Conditioning) is important in the design of medium to large industrial and office buildings like Life science & pharmaceutical industries. Where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors. In HVAC the major units are AHU (Air Handling Unit), Exhaust unit, Ventilation Unit, CAV (Constant Air Volume), VAV (Variable Air Volume). We have developed the PLC based BMS solution based on our experience & knowledge specifically in life science industries.