UNSOLVED How to calculate cumulative change in value only if certain condition is true
I have a process where different solvents are added to a single vessel via actuator valves. The total weight inside the vessel is captured from a load cell.
I want to create application where total amount of each solvent added to vessel is captured.
For that I want to log the total amount of weight increment in the vessel when the valve is open.
But I am not able to create a meta script point where total increment in weight when valve is in open condition is captured.
phildunlap last edited by phildunlap
It sounds like you want a numeric Meta point something like this...
//valve is the boolean point controlling the valve, updating ontext, logging on change //total is the numeric point measuring the weight in the vessel if(valve.value || my.time > valve.lastValue().time) return "no value"; //we'll not be logging here... set data type exception to ignore! //Okay, valve just closed var values = valve.last(2); var difference = total.value - total.pointValueBefore(values.time).value; return my.vaiue + difference;