openHAB

# Math Transformation Service

Transforms the input by applying simple math on it.

The available transformations are

  • MULTIPLY: multiply the state by a value
  • ADD: add a value to the state
  • DIVIDE: divide the state by a value
  • BITAND: perform a bit-wise AND of the state and a mask
  • BITOR: perform a bit-wise OR of the state and a mask
  • BITXOR: perform a bit-wise exclusive-OR of the state and a mask

The values need to be either decimals or strings. For bit-wise operations hexadecimal notation (e.g. 0x67) or binary notation (e.g. 0b00010000) are supported for both, value and state.

Arithmetic math Profiles have an optional configuration parameter itemName which allows to use an alternative Item State as value for the transformation. The Item State will be prioritized if given and different from UnDefType and interpretable as a decimal number.

# Full Example

Example Items:

Number multiply "Value multiplied by [MULTIPLY(1000):%s]" { channel="<channelUID>" }
Number add "Value added [ADD(5.1):%s]" { channel="<channelUID>" }
Number secondsToMinutes "Time [DIVIDE(60):%s]" { channel="<channelUID>" }
Number subtracted "Value subtracted [ADD(-1):%s]" { channel="<channelUID>" }
Number bitor "Value bitor [BITOR(0x27):%s]" { channel="<channelUID>" }

// Usage as a Profile
Number multiply "Value multiplied by [%.1f]" { channel="<channelUID>" [profile="transform:MULTIPLY", multiplicand="1000"] }
Number add "Value added [%.1f]" { channel="<channelUID>" [profile="transform:ADD", addend="5.1", itemName="multiply"] }
Number secondsToMinutes "Time [%d]" { channel="<channelUID>" [profile="transform:DIVIDE", divisor="60"] }
Number subtracted "Value subtracted [%.1f]" { channel="<channelUID>" [profile="transform:ADD", addend="-1"] }
Number bitand "Value bitand [%s]" { channel="<channelUID>" [profile="transform:BITAND", mask="0b00010000"] }

Example in Rules:

transform("MULTIPLY", "1000", myItem.state.toString)
transform("ADD", "5.1", myItem.state.toString)
transform("DIVIDE", "60", myItem.state.toString)
transform("ADD", "-1", myItem.state.toString)
transform("BITXOR", "127", myItem.state.toString)
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