MATLAB: Odeset: ‘Event’ as a threshold not zero

Question

I want to halt ode execution and save the output after one of the functions drops below a certain bound. I'm trying to do this with odeset('Events',@events) as follows

function [sol,soln] = fullSScollHM8
          % set parameters
          options = odeset('Events',@events);
          sol2 = ode15s(@fullSSfunc,[t0,tf],init,options);
  end
function dy = fullSSfunc(~,y)
       dy(1) = ...
       dy(7) = ...
end
function [value,isterminal,direction] = events(~,y)
      value = y(7) - 10^(-10);
           % detect when y(7) gets too low
      isterminal = 1; % halt integration
      direction = 0; % any which way
end

But if I output value, the code continues to run when y(7) drops below 10^(-10) because value is never zero. It seems like it should be straightforward to define an 'Event' within odeset not with a zero but rather a threshold. Can someone help me please?

Answer 1

        value = y(7) > 10^(-10);    %false, 0, when y(7) falls far enough

Remember, a negative value is not a 0 and the termination is to occur when a 0 is detected. The documentation does imply that a crossing should be detected, but does not really state it outright.