String that describes when this output goes into the energized state, as a function of a discrete input (or analog input for AIscout2). For AIscout, an integer >= 1 represents a discrete input, and '~' complements the input state. For AIscout2, this expression is a combination of analog and discrete inputs. Analog inputs are preceded by an 'A' and discrete inputs by a 'D'. The complement '~' works on a group of inputs. Also, multiple inputs may be specified as a comma separated list (1,3,5) or a hyphenated range (1-5). The expression is a combination of up to three ORs and as many ANDs as desired (i.e. a sum of 3 products). An empty string indicates manual control of the output point. AIscout examples: '15' (and deenergize when the input is normal). '~8' (and deenergize when the input is alarmed). AIscout2 examples: 'AH1,3,5' inputs 1, 3 and 5. '~AH1-2&AL3' (not in the alarm state) AND analog input 3 is in the low alarm state. 'AH*|AL*|D*' discrete input is alarmed.