get_theta_ist() can return numpy.float64 (Pot's transport delay line
is a numpy array internally), so the cooldown comparison produced a
numpy.bool_ instead of a plain bool. json.dumps() can't serialize that,
which silently killed the websocket connection's send loop the moment
a ramp step started - found by actually driving the feature through a
live server+GUI run instead of only unit-style tests with a directly
constructed controller.
jens
3a19e2a9dc