Maybe put the line conditioner after the UPS?
For my PC I've an APC Back-UPS CS 650VA (a line interactive UPS) and a APC Voltage regulator and I cannot put the voltage regulator
after the UPS because the voltage drops make it switch (almost always) in battery mode. This drains very quickly the battery and all shuts down in about 9 mins.
So I've put the voltage regulator
before the UPS and lowered the sensitivity on the Power Chute software (otherwise at every LOW/NORMAL status change on the voltage regulator the UPS try to compensate going in battery mode for a couple of seconds).
In this way I have voltage conditioning and back up power.
But every time the voltage regulator goes in LOW tension mode, I can hear a low, typical square wave noise sound coming out on my PC loudspeakers (powered from the same circuit): I guess this is due to the switching / approximate sinewave output coming out from the voltage regulator.
The point is that I don't know if using the same configuration (so providing an approximate sinewave power output) for my PSU and DMM will affect something on that instruments (or their PS).It's better to have frequent awful voltage drops or a stepped sinewave? I would start by complaining to the power company
I can't do it at the moment, I have to wait until I'm the real owner, not a tenant