Experimental Physics and
Industrial Control System

I suspect what you are seeing results from the asyn port not being
connected at the time of the IOC's initial scan.

Firstly, the name "StatusRegister" suggests to me that this value
should be read more than once on IOC startup.

imo. for robust operation some care should be taken anytime when
IOC and device don't share a power switch.

I try to avoid PINI with such devices, and instead use SCAN="10 second"
as a starting point for values which change slowly or only on device
power cycle.