The 1 per octave signal in Audulus is centered around 0, where 0 = A440 whereas VPO in modular starts at 0 = lowest note (don’t remember off top of my head).
The maximum output range of the ES-8 is 10 volts, and the maximum output of Audulus is -1 to 1. This means an Audulus value of -1 = -10 volts and a value of 1 = 10 volts.
So to translate Audulus pitch into VPO, divide by 10 and add 4 or 5 to shift the octaves up.
x/10+4
This is a quick and dirty way to convert. However, it’s not totally pitch perfect. @robertsyrett I believe has a utility that works really well for tuning oscillators in Audulus? In Audulus 4, we’ll have an oscillator auto tune feature that will listen to the output of an oscillator and create a pitch compensation profile that you can store and recall. The Expert Sleepers Silent Way software does this as well.