FUNCTION_BLOCK simple-dimmer

VAR_INPUT
  Ambient: REAL;
END_VAR

VAR_OUTPUT
  Power: REAL;
END_VAR

FUZZIFY Ambient
  RANGE := (0.000 .. 1.000);
  TERM DARK := Triangle 0.000 0.250 0.500;
  TERM MEDIUM := Triangle 0.250 0.500 0.750;
  TERM BRIGHT := Triangle 0.500 0.750 1.000;
END_FUZZIFY

DEFUZZIFY Power
  RANGE := (0.000 .. 1.000);
  TERM LOW := 0.250;
  TERM MEDIUM := 0.500;
  TERM HIGH := 0.750;
  METHOD : COGS;
  DEFAULT := nan;
END_DEFUZZIFY

RULEBLOCK 
  RULE 1 : if Ambient is DARK then Power is HIGH
  RULE 2 : if Ambient is MEDIUM then Power is MEDIUM
  RULE 3 : if Ambient is BRIGHT then Power is LOW
END_RULEBLOCK

END_FUNCTION_BLOCK