The "deadbandLowerLimit" property specifies the deadband's lower limit. It is an optional integer that defaults to “disabled”. A change is saveable when it is less than the deadband lower limit.

A deadband is a zone where data changes are ignored. For example, a deadband prevents an HVAC system from constantly switching between heating and cooling due to minor temperature fluctuations. A FairCom connector ignores values that are inside the deadband zone. 

The connector uses the following rules to implement a deadband range:

• When both the "deadbandLowerLimit" and "deadbandUpperLimit" properties are disabled, the connector ignores the deadband zone. 
• When the "deadbandLowerLimit" is disabled and the "deadbandUpperLimit" is set to a numeric value, the deadband range has an unlimited lower limit and a fixed upper limit. 
• When the "deadbandUpperLimit" is disabled and the "deadbandLowerLimit" is set to a numeric value, the deadband range has an unlimited upper limit and a fixed lower limit.

The following chart shows a connector saving values when they are outside the deadband range:

Scenario
A connector may collect temperature from an HVAC system once a second. Most collected values are between 70 and 73 degrees Fahrenheit. To ignore values in this range, set "deadbandLowerLimit" to 70, and "deadbandUpperLimit" to 73. To save the temperature once an hour – even if it has not changed, set "maxUnsavedEvents" to 3600.

Code example

{
 "api": "hub",
 "action": "createInput",
 "params": {
   "inputName": "modbusTCP",
   "serviceName": "modbus",
   "tableName": "modbusTableTCP",
   
   "dataCollectionIntervalMilliseconds": 1000,      
   "dataPersistenceStrategy": "onChange",

   "maxUnsavedEvents": 3600,
  
   "settings": {      
     "modbusProtocol": "TCP",
     "modbusServer": "127.0.0.1",
     "modbusServerPort": 502,
     
     "propertyMapList": [
       {
         "propertyPath": "temperature",
         "modbusDataAccess": "holdingregister",
         "modbusDataAddress": 4003,
         "modbusDataType": "int8Signed",

         "deadbandLowerLimit": 70,
         "deadbandUpperLimit": 73

       }
     ]
     
   }
 },
 "authToken": "replaceWithAuthTokenFromCreateSession"
}

Notes

• The connector uses this property only when the "dataPersistenceStrategy" is "onChange". 
• The following properties work together to save meaningful data changes.
  • "dataPersistenceStrategy"
  • "maxUnsavedEvents"
  • "normalLowerLimit"
  • "normalUpperLimit"
  • "deadbandLowerLimit"
  • "deadbandUpperLimit"
  • "significantMagnitude" 
  • "onChangeScope"
  • "onChangeScopeTags"
  • "onChangeTrigger"
  • "onChangeTriggerTags"