Open loop and narrowband o2 sensor

[koollude]

Setup
2000 prelude (stock h22a4), s300 p28, factory primary o2 sensor installed, no wideband input for datalogging purposes (LM1 wideband permenantly installed in its own bung, w/custom remote in-dash display used for monitoring AFR's and tuning, but NOT YET spliced into ecu for datalogging).

Question:
While datalogging and switching from closed loop into open loop, the o2 sensor reads a constant 3.8 volts (AF constant at 1.2). Is this because the ecu disables the narrowband o2 sensor in open loop, so I'm seeing no signal, or constant 3.8v from the ecu?

Datalog attached, look at Graph / Closed Loop

[Spunkster]

in open loop you will not get a reading from the O2 sensor.

[koollude]

Thanks.