Determine if temperature sensor is faulty

Applicable Systems

  • Primary: AHU, RTU, MUA, ERV, BLR, CHLR
  • Secondary: HP, FCU, UV, UH

Description / Method

Monitors temperature sensor readings and triggers an insight if the reading is outside of an acceptable range (0 to 45 deg C) for more than 2 hours a week (user adjustable). This temperature sensor readings are analyzed only when the equipment is on (example: Supply Air Temperature, Mixed Air Temperature), or when the space is occupied (Room Temperature).

Logic

Normalize inputs to 15 min intervals. Check the temperature is out of range. Filter results where equipment is not on or the building is not occupied. Sum these hours over the week. Store the weekly hours in a CTL.

CTL = sum hours over the week {
   when occupired {
       temp Out of range = if(Temp> high limit  or temp < low limit)
      }
   }
if(Sum > threshold,  Insight)
Determine if temperature sensor is faulty
  1. Input sensor(s) faulty or miscalibrated. Verify input sensor(s) operation.

Message

The Temperature sensor is faulty (outside of acceptable range). Verify input sensor operation.

Rule Template Type

  • Insight Type: Fault Detection
  • Trigger Type: Active High

Default Priority

Low

Inputs

InputsUnitsTagsDescription
Temperature°C/°Fmixed|discharge|return|fresh|room|zone,air,temp,sensorEquipment On/Off Indicator
Equip ON0/1cmd|status|occupiedDesired temperature of water leaving the chiller

Constants

InputsUnitsDefault ValueDescription
High Threshold°C/°F45Upper limit on allowed reported temperature
Low Threshold°C/°F0Lower limit on allowed reported temperature
Acceptable Hours per Weekhours2Allowed hours with sensor deviation

Output Calculated Trend Logs

Output CTLUnitsFrequencyDescription
SlowStartupDailyCount dailyNumber of times the slow start condition occurs in a day