I copied and pasted your code in to the IDE and of course it complies w/o errors.
What I noticed is that this code is designed for inputing three different temp sensors.
My objective is to use three DIGITAL inputs to trigger a recording of one COMMON temp sensor.
In other words when the boiler lockout input signal changes state in my heating system I want to record the hot water tank temp. If the tank aquastat calls for heat I want to record the tank temp. And lastly when the boiler RUN command is issued I want to record the tank temp.
I am going to study that link you provided about circular arrays and see if it is adaptable to my needs.
thanks for your input... 